RFR: 8369219: JNI::RegisterNatives causes a memory leak in CodeCache [v5]

[Francesco Andreuzzi]

> I propose to amend `nmethod::is_cold` to let GC collect not-entrant native `nmethod` instances.
> 
> Passes tier1 and tier2 (fastdebug).

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

  nn

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27742/files
  - new: https://git.openjdk.org/jdk/pull/27742/files/8ea13b6e..98754ee8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27742&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27742&range=03-04

  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