One of the tests in the Lucene testsuite fails with a wrong result.

Steps to reproduce:
1. Download Lucene: https://lucene.apache.org/core/downloads.html (tested with 8.4.1)
2. Unpack and setup Ant build according to instructions (https://github.com/apache/lucene-solr/blob/master/lucene/BUILD.txt)
3. Run test:
export JAVA_HOME=/path/to/jdk-under-test
ant beast -Dbeast.iters=2000 -Dtestcase=TestBagOfPostings -Dargs="-XX:+UnlockExperimentalVMOptions -XX:+UseShenandoahGC"

ant beast runs the test 2000 times. It always failed for me before completing 2000 runs.

The test does not seem to fail with -XX:-TieredCompilation nor does it seem to fail with -Xint, which indicates (but does not prove) that it's related to C1.

It fails in different ways, but always similar in that some result is wrong:

  [beaster] Started J0 PID(23718@localhost).
  [beaster] 2> Jan 23, 2020 6:17:15 PM com.carrotsearch.randomizedtesting.RandomizedRunner$QueueUncaughtExceptionsHandler uncaughtException
  [beaster] 2> WARNING: Uncaught exception in thread: Thread[Thread-0,5,TGRP-TestBagOfPostings]
  [beaster] 2> java.lang.RuntimeException: java.lang.IllegalArgumentException: maxMergedSegmentMB must be >=0 (got -7.478635795308384E240)
  [beaster] 2> at __randomizedtesting.SeedInfo.seed([7CE6ED455350A485]:0)
  [beaster] 2> at org.apache.lucene.index.TestBagOfPostings$1.run(TestBagOfPostings.java:114)
  [beaster] 2> Caused by: java.lang.IllegalArgumentException: maxMergedSegmentMB must be >=0 (got -7.478635795308384E240)
  [beaster] 2> at org.apache.lucene.index.TieredMergePolicy.setMaxMergedSegmentMB(TieredMergePolicy.java:161)
  [beaster] 2> at org.apache.lucene.util.LuceneTestCase.maybeChangeLiveIndexWriterConfig(LuceneTestCase.java:1266)
  [beaster] 2> at org.apache.lucene.index.RandomIndexWriter.maybeFlushOrCommit(RandomIndexWriter.java:200)
  [beaster] 2> at org.apache.lucene.index.RandomIndexWriter.addDocument(RandomIndexWriter.java:194)
  [beaster] 2> at org.apache.lucene.index.TestBagOfPostings$1.run(TestBagOfPostings.java:111)
  [beaster] 2>
  [beaster] 2> NOTE: reproduce with: ant test -Dtestcase=TestBagOfPostings -Dtests.method=test -Dtests.seed=7CE6ED455350A485 -Dtests.slow=true -Dtests.badapples=true -Dtests.locale=en-AG -Dtests.timezone=Antarctica/Troll -Dtests.asserts=true -Dtests.file.encoding=UTF-8
  [beaster] [19:17:14.075] ERROR 1.74s | TestBagOfPostings.test <<<
  [beaster] > Throwable #1: java.lang.AssertionError: expected:<412> but was:<410>
  [beaster] > at org.junit.Assert.fail(Assert.java:88)
  [beaster] > at org.junit.Assert.failNotEquals(Assert.java:834)
  [beaster] > at org.junit.Assert.assertEquals(Assert.java:645)
  [beaster] > at org.junit.Assert.assertEquals(Assert.java:631)
  [beaster] > at org.apache.lucene.index.TestBagOfPostings.test(TestBagOfPostings.java:131)
  [beaster] > at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  [beaster] > at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  [beaster] > at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  [beaster] > at java.base/java.lang.reflect.Method.invoke(Method.java:564)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner.invoke(RandomizedRunner.java:1750)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner$8.evaluate(RandomizedRunner.java:938)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner$9.evaluate(RandomizedRunner.java:974)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner$10.evaluate(RandomizedRunner.java:988)
  [beaster] > at org.apache.lucene.util.TestRuleSetupTeardownChained$1.evaluate(TestRuleSetupTeardownChained.java:49)
  [beaster] > at org.apache.lucene.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:45)
  [beaster] > at org.apache.lucene.util.TestRuleThreadAndTestName$1.evaluate(TestRuleThreadAndTestName.java:48)
  [beaster] > at org.apache.lucene.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:64)
  [beaster] > at org.apache.lucene.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:47)
  [beaster] > at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  [beaster] > at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:368)
  [beaster] > at com.carrotsearch.randomizedtesting.ThreadLeakControl.forkTimeoutingTask(ThreadLeakControl.java:817)
  [beaster] > at com.carrotsearch.randomizedtesting.ThreadLeakControl$3.evaluate(ThreadLeakControl.java:468)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner.runSingleTest(RandomizedRunner.java:947)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner$5.evaluate(RandomizedRunner.java:832)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner$6.evaluate(RandomizedRunner.java:883)
  [beaster] > at com.carrotsearch.randomizedtesting.RandomizedRunner$7.evaluate(RandomizedRunner.java:894)
  [beaster] > at org.apache.lucene.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:45)
  [beaster] > at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  [beaster] > at org.apache.lucene.util.TestRuleStoreClassName$1.evaluate(TestRuleStoreClassName.java:41)
  [beaster] > at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  [beaster] > at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  [beaster] > at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  [beaster] > at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  [beaster] > at org.apache.lucene.util.TestRuleAssertionsRequired$1.evaluate(TestRuleAssertionsRequired.java:53)
  [beaster] > at org.apache.lucene.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:47)
  [beaster] > at org.apache.lucene.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:64)
  [beaster] > at org.apache.lucene.util.TestRuleIgnoreTestSuites$1.evaluate(TestRuleIgnoreTestSuites.java:54)
  [beaster] > at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  [beaster] > at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:368)
  [beaster] > at java.base/java.lang.Thread.run(Thread.java:832)
  [beaster] > Throwable #2: com.carrotsearch.randomizedtesting.UncaughtExceptionError: Captured an uncaught exception in thread: Thread[id=28, name=Thread-0, state=RUNNABLE, group=TGRP-TestBagOfPostings]
  [beaster] > Caused by: java.lang.RuntimeException: java.lang.IllegalArgumentException: maxMergedSegmentMB must be >=0 (got -7.478635795308384E240)
  [beaster] > at __randomizedtesting.SeedInfo.seed([7CE6ED455350A485]:0)
  [beaster] > at org.apache.lucene.index.TestBagOfPostings$1.run(TestBagOfPostings.java:114)
  [beaster] > Caused by: java.lang.IllegalArgumentException: maxMergedSegmentMB must be >=0 (got -7.478635795308384E240)
  [beaster] > at org.apache.lucene.index.TieredMergePolicy.setMaxMergedSegmentMB(TieredMergePolicy.java:161)
  [beaster] > at org.apache.lucene.util.LuceneTestCase.maybeChangeLiveIndexWriterConfig(LuceneTestCase.java:1266)
  [beaster] > at org.apache.lucene.index.RandomIndexWriter.maybeFlushOrCommit(RandomIndexWriter.java:200)
  [beaster] > at org.apache.lucene.index.RandomIndexWriter.addDocument(RandomIndexWriter.java:194)
  [beaster] > at org.apache.lucene.index.TestBagOfPostings$1.run(TestBagOfPostings.java:111)
  [beaster] 2> NOTE: leaving temporary files on disk at: /home/rkennke/src/lucene-8.4.1/build/core/test/J0/temp/lucene.index.TestBagOfPostings_7CE6ED455350A485-001
  [beaster] 2> NOTE: test params are: codec=Asserting(Lucene84): {field=PostingsFormat(name=LuceneVarGapFixedInterval)}, docValues:{}, maxPointsInLeafNode=565, maxMBSortInHeap=7.837812716170918, sim=Asserting(org.apache.lucene.search.similarities.AssertingSimilarity@9a5e068), locale=en-AG, timezone=Antarctica/Troll
  [beaster] 2> NOTE: Linux 4.18.0-147.3.1.el8_1.x86_64 amd64/N/A 15-internal (64-bit)/cpus=32,threads=1,free=509967512,total=536870912
  [beaster] 2> NOTE: All tests run in this JVM: [TestBagOfPostings]
  [beaster]
  [beaster] Tests with failures [seed: 7CE6ED455350A485]:
  [beaster] - org.apache.lucene.index.TestBagOfPostings.test