8166724: gc/g1/TestHumongousShrinkHeap.java fails with OOME

[Leonid Mesnik]

Hi

Could you please review following test fix. Test failed because initial 
heap size was the same as maximum heap size. So OOME was thrown while 
filling heap.

Test has been updated to check that initial heap doesn't equals to 
maximum heap and could be filled without getting OOME.

webrev: http://cr.openjdk.java.net/~lmesnik/8166724/webrev.00/ 
<http://cr.openjdk.java.net/%7Elmesnik/8166724/webrev.00/>

bug: https://bugs.openjdk.java.net/browse/JDK-8166724

Leonid