RFR: 8350549: MethodHandleProxies.WRAPPER_TYPES is not thread-safe

[Chen Liang]

Use a thread-safe ReferencedKeySet instead of a WeakHashMap key set.

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Commit messages:
 - 8350549: MethodHandleProxies.WRAPPER_TYPES is not thread-safe

Changes: https://git.openjdk.org/jdk/pull/23757/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23757&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350549
  Stats: 4 lines in 1 file changed: 1 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/23757.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23757/head:pull/23757

PR: https://git.openjdk.org/jdk/pull/23757