RFR: 8330181: Move PcDesc cache from nmethod header

[Vladimir Kozlov]

Currently PcDescCache (32 bytes: PcDesc* _pc_descs[4]) is allocated in `nmethod` header.

Moved PcDescContainer (which includes cache) to C heap similar to ExceptionCache to reduce size of `nmethod` header and remove WXWrite transition when we update the cache in `PcDescCache::add_pc_desc()`.

Tested tier1-4,stress,xcomp and performance.

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Commit messages:
 - 8330181: Move PcDesc cache from nmethod header

Changes: https://git.openjdk.org/jdk/pull/18895/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18895&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8330181
  Stats: 114 lines in 2 files changed: 41 ins; 32 del; 41 mod
  Patch: https://git.openjdk.org/jdk/pull/18895.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18895/head:pull/18895

PR: https://git.openjdk.org/jdk/pull/18895