RFR: 8317538: RSA have scalability issue for high vCPU numbers [v3]

[Ben Perez]

> Modified `getService` method to prevent caching of `ServiceKey`, which was negatively impacting multithreaded performance

Ben Perez has updated the pull request incrementally with one additional commit since the last revision:

  changed cache to use threadlocal

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Changes:
  - all: https://git.openjdk.org/jdk/pull/16403/files
  - new: https://git.openjdk.org/jdk/pull/16403/files/c33e1cd9..7ddc66eb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16403&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16403&range=01-02

  Stats: 9 lines in 1 file changed: 5 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/16403.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16403/head:pull/16403

PR: https://git.openjdk.org/jdk/pull/16403