[jdk21u-dev] RFR: 8314220: Configurable InlineCacheBuffer size

[Aleksey Shipilev]

Transplanted from https://github.com/openjdk/jdk21u/pull/419.

Clean backport to allow tuning ICBuffer size, important to dodge many ICBufferFull safepoints.

Additional testing:
 - [x] Eyeballing `-XX:+TraceICBuffer` output on ad-hoc workloads

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Commit messages:
 - Backport a40d8d97e84d88d1a65aba81bfc09339be95e427

Changes: https://git.openjdk.org/jdk21u-dev/pull/6/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=6&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314220
  Stats: 11 lines in 4 files changed: 8 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/6.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/6/head:pull/6

PR: https://git.openjdk.org/jdk21u-dev/pull/6