RFR: 8369219: JNI::RegisterNatives can cause a memory leak in CodeCache [v3]

[Francesco Andreuzzi]

> I propose to amend the check in `nmethod::is_cold` to allow not-entrant native `nmethod` instances to be collected during GC.
> 
> Passes tier1 and tier2 (fastdebug).

Francesco Andreuzzi has updated the pull request incrementally with one additional commit since the last revision:

  fix summary

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27742/files
  - new: https://git.openjdk.org/jdk/pull/27742/files/b3eae893..6bba7687

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27742&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27742&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27742.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27742/head:pull/27742

PR: https://git.openjdk.org/jdk/pull/27742