RFR 8208697: vmTestbase/metaspace/stressHierarchy/stressHierarchy012/TestDescription.java fails with OutOfMemoryError: Metaspace

[coleen.phillimore at oracle.com]

Summary: remove timeoutHandler class and let Stresser handle timeout, 
remove 30 threads filling metaspace, and remove related unused files.

This also fixes a compilation warning in GeneratingClassLoader.java 
(unreachable try block).

open webrev at http://cr.openjdk.java.net/~coleenp/8208697.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8208697

Tested 300+ times without failure.  Usual rate is 2-100.

Thanks,
Coleen