ZGC: TestUncommit.java fails due to "Exception: Uncommitted too fast"

The following test failed in the JDK15 CI:

gc/z/TestUncommit.java

Here's a snippet from the log file:

----------System.err:(14/849)----------
java.lang.Exception: Uncommitted too fast
at gc.z.TestUncommit.test(TestUncommit.java:101)
at gc.z.TestUncommit.main(TestUncommit.java:131)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
at java.base/java.lang.Thread.run(Thread.java:832)

JavaTest Message: Test threw exception: java.lang.Exception: Uncommitted too fast
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.Exception: Uncommitted too fast
----------rerun:(43/4597)*----------