RFR: 8263567: gtests don't terminate the VM safely [v2]

[David Holmes]

> Please review this fix to shutdown cleanly any JVMs created by gtests that aren't aborted.
> 
> Testing:
>   - manual instrumentation to check all JVM construction and then deletion during gtest runs
>   - local gtest testing
>   - tiers 1-3 gtest testing
> 
> Thanks,
> David

David Holmes has updated the pull request incrementally with one additional commit since the last revision:

  Addressed comments from @tstuefe

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4986/files
  - new: https://git.openjdk.java.net/jdk/pull/4986/files/ae5dc8f0..f9a3bd80

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4986&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4986&range=00-01

  Stats: 21 lines in 1 file changed: 6 ins; 5 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4986.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4986/head:pull/4986

PR: https://git.openjdk.java.net/jdk/pull/4986