RFR: 8259242: vmTestbase/vm/mlvm/mixed/stress/java/findDeadlock/TestDescription.java timed out

[Coleen Phillimore]

This change makes the DictionaryEntry pd_set lock free, because when I set a low SafepointTimeout on the findDeadlock test, these threads were waiting on the ProtectionDomainSet_lock.  This lock is a singleton that's taken for every dictionary entry.

I don't know if this change will make the test never timeout again, because removing this lock caused us to hit a low SafepointTimeout on another _no_safepoint_check lock that is not so easy to eradictate.

Tested with tiers 1-3.  There's a test that exercises this code in runtime/Dictionary/ProtectionDomainCacheTest.java.

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Commit messages:
 - 8259242: vmTestbase/vm/mlvm/mixed/stress/java/findDeadlock/TestDescription.java timed out

Changes: https://git.openjdk.java.net/jdk/pull/3362/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3362&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259242
  Stats: 121 lines in 9 files changed: 61 ins; 34 del; 26 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3362.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3362/head:pull/3362

PR: https://git.openjdk.java.net/jdk/pull/3362