RFR: 8293584: CodeCache::old_nmethods_do incorrectly filters is_unloading nmethods [v2]

[Coleen Phillimore]

> I fixed the code to also include is_unloading nmethods.  I couldn't write a dedicated test for this.
> Tested with tier1-4,6.  Also tried to reproduce another redefinition bug with this change, which didn't reproduce, but not caused by this change.

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Add a comment.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/11243/files
  - new: https://git.openjdk.org/jdk/pull/11243/files/de0a72c9..91dc37be

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11243&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11243&range=00-01

  Stats: 3 lines in 1 file changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/11243.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11243/head:pull/11243

PR: https://git.openjdk.org/jdk/pull/11243