RFR [8]: Test bug: test library and flags in TestHeapAlloc

[Aleksey Shipilev]

Current TestHeapAlloc test fails in 8u:

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TEST: gc/shenandoah/TestHeapAlloc.java
TEST JDK:
/home/shade/trunks/shenandoah-jdk8/build/linux-x86_64-normal-server-fastdebug/images/j2sdk-image

TEST RESULT: Error. Can't find library: /test/lib
--------------------------------------------------

This is because 9 and 10 have different testlibrary layouts, and it also have different expectations
about VM flags.

Fix:
 http://cr.openjdk.java.net/~shade/shenandoah/tests-8u-heapalloc/webrev.01/

Thanks,
-Aleksey