RFR: Print messages and VM streams on VM failure

[Aleksey Shipilev]

Currently, jcstress does not print those when VM fails, which hinders the debugging.

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Commit messages:
 - Print messages and error streams on VM failure

Changes: https://git.openjdk.java.net/jcstress/pull/24/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jcstress&pr=24&range=00
  Stats: 66 lines in 2 files changed: 17 ins; 27 del; 22 mod
  Patch: https://git.openjdk.java.net/jcstress/pull/24.diff
  Fetch: git fetch https://git.openjdk.java.net/jcstress pull/24/head:pull/24

PR: https://git.openjdk.java.net/jcstress/pull/24