RFR: 8316958: Add test for unstructured locking

Tue Sep 26 14:20:40 UTC 2023

In my original lightweight-locking PR, I had a testcase that exercises unstructured locking, which is permitted by the JVM spec, but not generated by javac, and thus not executed anywhere. JITs don't compile unstructured-locked code, therefore any code which attempts this would be slow anyway.

Testing:
 - [x] runtime/locking

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Commit messages:
 - 8316958: Add test for unstructured locking

Changes: https://git.openjdk.org/jdk/pull/15925/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15925&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316958
  Stats: 56 lines in 1 file changed: 56 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15925.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15925/head:pull/15925

PR: https://git.openjdk.org/jdk/pull/15925