[JVMCI] runtime/ClassUnload/ConstantPoolDependsTest.java fails on libgraal

This test still fails transiently on libgraal on fastdebug + Xcomp.

jdk.test.lib.classloader.ClassUnloadCommon$TestFailure: Test failed: should be unloaded
at jdk.test.lib.classloader.ClassUnloadCommon.failIf(ClassUnloadCommon.java:54)
at ConstantPoolDependsTest.main(ConstantPoolDependsTest.java:85)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1575)