Test gc/TestFullGCCount.java failed with exception java.lang.RuntimeException: FAILED: System.gc collections miscounted.

This failure happened only with CMS and -XX:+ExplicitGCInvokesConcurrent.

----------System.err:(15/988)----------
Collector 'ConcurrentMarkSweep' has increment 2 at iteration 1

java.lang.RuntimeException: FAILED: System.gc collections miscounted.
at TestFullGCCount.main(TestFullGCCount.java:84)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-internal/Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(java.base@9-internal/NativeMethodAccessorImpl.java:62)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-internal/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-internal/Method.java:535)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:110)
at java.lang.Thread.run(java.base@9-internal/Thread.java:843)

JavaTest Message: Test threw exception: java.lang.RuntimeException: FAILED: System.gc collections miscounted.
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: FAILED: System.gc collections miscounted.