RFR (XS) 8222468: [TESTBUG] vmTestbase/metaspace/flags/maxMetaspaceSize/TestDescription.java fails with java.lang.NoClassDefFoundError

[coleen.phillimore at oracle.com]

Summary: Preload StackTraceElement$HashedModules in test.

Ran test 200x with fix, usually fails 6-10 times without.  Running 
sanity tier1 tests now.

open webrev at http://cr.openjdk.java.net/~coleenp/2019/8222468.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8222468

Thanks,
Coleen