RFR(L) : 8199370: [TESTBUG] Open source vm testbase GC tests

[Igor Ignatyev]

http://cr.openjdk.java.net/~iignatyev/8199370/webrev.00/index.html
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Hi all,

could you please review the patch which open sources GC tests from vm testbase? it introduces the following test groups:
- vmTestbase_vm_g1classunloading
- vmTestbase_vm_gc_compact
- vmTestbase_vm_gc_concurrent
- vmTestbase_vm_gc_container
- vmTestbase_vm_gc_juggle
- vmTestbase_vm_gc_locker
- vmTestbase_vm_gc_ref
- vmTestbase_vm_gc_misc

besides these test groups, which split tests by functionality under test, the patch also adds test groups used only for test selection purposes:
- vmTestbase_vm_gc which includes all vmTestbase_vm_gc_* test groups
- vmTestbase_vm_gc_quick -- "quick" tests from vmTestbase_vm_gc test group
- vmTestbase_largepages which consists of tests which are believed to be good candidate to test largepage. this group is used in our testing w/ external vm flags and/or on pre-configured hosts. 

As usually w/ VM testbase code, these tests are old, they have been run in hotspot testing for a long period of time. Originally, these tests were run by a test harness different from jtreg and had different build and execution schemes, some parts couldn't be easily translated to jtreg, so tests might have actions or pieces of code which look weird. In a long term, we are planning to rework them.

JBS: https://bugs.openjdk.java.net/browse/JDK-8199370
webrev: http://cr.openjdk.java.net/~iignatyev/8199370/webrev.00/index.html

Thanks,
-- Igor