[jdk21u] RFR: 8314024: SIGSEGV in PhaseIdealLoop::build_loop_late_post_work due to bad immediate dominator info [v2]

[Roman Marchenko]

> Clean backport.
> Tests in compiler/loopopts are passed.

Roman Marchenko has updated the pull request incrementally with one additional commit since the last revision:

  Empty commit to trigger tests

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

Changes:
  - all: https://git.openjdk.org/jdk21u/pull/124/files
  - new: https://git.openjdk.org/jdk21u/pull/124/files/f3c4215e..05462dc3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u&pr=124&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u&pr=124&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u/pull/124.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/124/head:pull/124

PR: https://git.openjdk.org/jdk21u/pull/124