RFR: 8302870: More information needed from failures in vmTestbase ThreadUtils.waitThreadState

[Kevin Walls]

Test update to make failures such as JDK-8076494 more informative.

Waiting for a thread to change state: give more time (to distinguish a real deadlock from some other delay), and log the thread stackframes when the expected state change is not observed.

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Commit messages:
 - import tweak
 - 8302870: More information needed from failures in vmTestbase ThreadUtils.waitThreadState

Changes: https://git.openjdk.org/jdk/pull/12661/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12661&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302870
  Stats: 28 lines in 1 file changed: 23 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/12661.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12661/head:pull/12661

PR: https://git.openjdk.org/jdk/pull/12661