RFR: 8263567: gtests don't terminate the VM safely

[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

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Commit messages:
 - update copyright year
 - 8263567: gtests don't terminate the VM safely

Changes: https://git.openjdk.java.net/jdk/pull/4986/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4986&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263567
  Stats: 50 lines in 2 files changed: 41 ins; 2 del; 7 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