RFR(S): 8130434: [TESTBUG] Harden TestLargePageUseForAuxMemory for more page size combinations.

[Lindenmaier, Goetz]

Hi,

this test wants to enforce large page usage for the card table etc.
It fails for certain page sizes we see on ppc, linux and aix.

On some, large page size == page size holds and this test fails:
"To test we would require to use an invalid heap size (assert failed: 33554432 > 33554432)"
Fix: Just skip the test in this case as it's pointless.

We have a machine with page size = 64K and large page size 4M.
In this case heapSizeDiffForBitmap was too small to reduce the heap size.
Due to the big value for the normal page size heap alignment is > largePageSize
and the heap size was aligned up to the original value.
Error: "'G1 'Prev Bitmap': pg_sz=65536' missing from stdout/stderr"
Fix: consider heap alignement for heapSizeDiffForBitmap.

Please review this change.  I please need a sponsor.
http://cr.openjdk.java.net/~goetz/webrevs/8130434-lrgPg/webrev.01/

Besides ppc, I tested this change on  linuxx86_64, sun_64 and darwin_x86_64.

Best regards,
  Goetz