RFR: Update to test java/lang/management/MemoryMXBean/ResetPeakMemoryUsage.java

[Staffan Larsen]

This test had a number of problems reported against it:

http://bugs.sun.com/view_bug.do?bug_id=7148492
http://bugs.sun.com/view_bug.do?bug_id=6980985
http://bugs.sun.com/view_bug.do?bug_id=7181907

This overhaul of the test tries to address all of these and improve the test robustness. The changes I have done are:

- Make sure the allocated large object is not easy to optimize away by storing it in a public field.
- Removed the dynamic calculation of the large object's size since this sometimes caused problems.
- Added GC configuration parameters to make sure the large object is allocated in the old gen.
- Added GC configuration parameters to run the test with all GC algorithms.
- Changed the printMemoryUsage() method to take MemoryUsages as parameters so it prints the same values as were used for comparisons.
- Changed some incorrect '>' to '<' in printouts.
- Removed the assumption that peak usage after the GC should be the same as before the GC. This is not true since "stuff" may have been moved from younger generations into the old gen thereby increasing the heap.

webrev: http://cr.openjdk.java.net/~sla/7148492/webrev.00/

I've been running the test through JPRT a couple of times to try to ensure that it always passes.

Thanks,
/Staffan