RFR: JDK-8056237 [TESTBUG] gc/g1/TestHumongousShrinkHeap.java fails due to OOM

[Andrey Zakharov]

Hi, team.
Here is patch for existing test for G1 TestHumongousShrinkHeap.java.
It just makes test respect available memory, and small code changes - 
renaming function.

webrev:
http://cr.openjdk.java.net/~fzhinkin/azakharov/8056237/webrev.00/
bug:
https://bugs.openjdk.java.net/browse/JDK-8056237


Testing in aurora started as 582911.ute.hs_jtreg.accept.full . But 
according to https://bugs.openjdk.java.net/browse/JDK-8056043 its still 
fails with product bug.
This fix only fixes OOMs on low boxes.

Thanks.