[jdk18u] RFR: 8284848: C2: Compiler blackhole arguments should be treated as globally escaping [v2]

[Aleksey Shipilev]

> Unclean backport to improve Blackhole - EA interactions. The backport is not clean, because `IRNode` needs missing constants, and `set_escape_state` does not accept third argument (description) in 18u.
> 
> Additional testing:
>  - [x] `compiler/c2/irTests/blackhole` fail without the patch, pass with it
>  - [x] `compiler/blackhole` continue to pass

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into JDK-8284848-blackhole-ea
 - Backport 5629c7555f9bb779c57f45dfb071abbb1d87bb7d

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

Changes:
  - all: https://git.openjdk.java.net/jdk18u/pull/118/files
  - new: https://git.openjdk.java.net/jdk18u/pull/118/files/4d8669a4..b58ac060

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk18u&pr=118&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk18u&pr=118&range=00-01

  Stats: 327 lines in 7 files changed: 314 ins; 6 del; 7 mod
  Patch: https://git.openjdk.java.net/jdk18u/pull/118.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18u pull/118/head:pull/118

PR: https://git.openjdk.java.net/jdk18u/pull/118