RFR: 8310264: In PhaseChaitin::Split defs and phis are leaked [v2]

[Johan Sjölen]

> Hi,
> 
> `defs` and `phis` are leaked as they are resource allocated but not protected by a `ResourceMark`. The intention might have been for these to also live in the `split_arena`.. This change is the most conservative one, however, and does fix the memory leak.
> 
> Please consider, thanks.
> 
> Johan

Johan Sjölen has updated the pull request incrementally with three additional commits since the last revision:

 - Skip the resource mark, add in separate temporary arenas for each.
 - Allocate whole of VectorSet on arena
 - Stack allocate

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14530/files
  - new: https://git.openjdk.org/jdk/pull/14530/files/1b0c549a..820b0841

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14530&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14530&range=00-01

  Stats: 20 lines in 1 file changed: 4 ins; 2 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/14530.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14530/head:pull/14530

PR: https://git.openjdk.org/jdk/pull/14530