RFR (S): 8006088: Incompatible heap size flags accepted by VM

[Thomas Schatzl]

Hi all,

  please review the latest changes for this CR, taking Leonid's comments
into account.

Differences:
 - changed names of the test cases, since because by moving it from a CR
specific directory into a more generic one, the test names were too
generic.
 - removed the use of test.java.opts for calling the VM that executes
some whitebox method as it may interfere with execution
 - factored out method to execute a VM running a custom class with the
whitebox api enabled. More refactoring later in 8012591.
 - no functional changes

Ergonomics behavior reference:
http://cr.openjdk.java.net/~tschatzl/8006088/webrev.6/XmsInitialHeapSizeErgo.html

Bugs.sun.com:
http://bugs.sun.com/view_bug.do?bug_id=8006088

JIRA:
https://jbs.oracle.com/bugs/browse/JDK-8006088

Webrev:
http://cr.openjdk.java.net/~tschatzl/8006088/webrev.9/

Testing:
JPRT, manual testing

Thanks,
  Thomas