[JDK-8322630](https://bugs.openjdk.org/browse/JDK-8322630) / #17495 removed the the concept of ICStubs, InlineCache buffers and related safepoints.
There are a handfull of references and auxiliary constructs still in the code, I propose we clean these out. This removes the unused: * Experimental `InlineCacheBufferSize` option * `InlineCacheBuffer_lock` mutex * `Thread::_missed_ic_stub_refill_verifier` field * `VM_ICBufferFull` VM operation ------------- Commit messages: - 8341168: Cleanup dead code after JDK-8322630 Changes: https://git.openjdk.org/jdk/pull/21255/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21255&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8341168 Stats: 39 lines in 10 files changed: 0 ins; 35 del; 4 mod Patch: https://git.openjdk.org/jdk/pull/21255.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21255/head:pull/21255 PR: https://git.openjdk.org/jdk/pull/21255
