Request for reviews (S): 6999491: non-zero COOPs are used when they should not

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/6999491/webrev

Fixed 6999491: non-zero COOPs are used when they should not

Regression introduced by fix for 6984368 bug.
The expression in max_heap_for_compressed_oops() produces
incorrect result when HeapBaseMinAddress > OopEncodingHeapMax.

HeapBaseMinAddress should be used only for a default heap
size calculation.
Added heap size to PrintCompressedOopsMode output.