Fix flaky test: org.apache.cassandra.cql3.MemtableSizeTest.testTruncationReleasesLogSpace

java.lang.reflect.InaccessibleObjectException: Unable to make field private final jdk.management.jfr.StreamManager jdk.management.jfr.FlightRecorderMXBeanImpl.streamHandler accessible: module jdk.management.jfr does not "opens jdk.management.jfr" to unnamed module @6db9f5a4
	at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:340)
	at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:280)
	at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:176)
	at java.base/java.lang.reflect.Field.setAccessible(Field.java:170)
	at org.github.jamm.MemoryMeter.addFieldChildren(MemoryMeter.java:330)
	at org.github.jamm.MemoryMeter.measureDeep(MemoryMeter.java:269)
	at org.apache.cassandra.utils.ObjectSizes.measureDeep(ObjectSizes.java:216)
	at org.apache.cassandra.cql3.MemtableSizeTest.testSize(MemtableSizeTest.java:121)
	at org.apache.cassandra.Util.runCatchingAssertionError(Util.java:644)
	at org.apache.cassandra.Util.flakyTest(Util.java:669)
	at org.apache.cassandra.cql3.MemtableSizeTest.testTruncationReleasesLogSpace(MemtableSizeTest.java:61)
	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)