RFR: 8330181: Move PcDesc cache from nmethod header [v2]

[Vladimir Kozlov]

> Currently PcDescCache (32 bytes in 64-bit VM: 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 to remove WXWrite transition when we update the cache in `PcDescCache::add_pc_desc()`.
> 
> Removed `PcDescSearch` class which was leftover from `CompiledMethod` days.
> 
> Tested tier1-4,stress,xcomp and performance.

Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:

  Remove unneeded ThreadWXEnable

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/18895/files
  - new: https://git.openjdk.org/jdk/pull/18895/files/88617209..cd1453b9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18895&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18895&range=00-01

  Stats: 6 lines in 2 files changed: 1 ins; 4 del; 1 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