RFR: 8305404: Compile_lock not needed for InstanceKlass::implementor()

[Coleen Phillimore]

See CR for details.
Tested with tier1-4, 7, 8.

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Commit messages:
 - 8305404: Compile_lock not needed for InstanceKlass::implementor()

Changes: https://git.openjdk.org/jdk/pull/13458/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13458&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305404
  Stats: 11 lines in 2 files changed: 0 ins; 5 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/13458.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13458/head:pull/13458

PR: https://git.openjdk.org/jdk/pull/13458