RFR: 8319879: Stress mode to randomize incremental inlining decision [v4]

[Tobias Hartmann]

> We had quite a few C2 bugs in the past that only reproduced with a specific sequence of incremental inlining (for example, [JDK-8319764](https://bugs.openjdk.org/browse/JDK-8319764)). We should randomize the incremental inlining decision to trigger these code paths more frequently.
> 
> I did some testing with the flag enabled and I hit [JDK-8319764](https://bugs.openjdk.org/browse/JDK-8319764) and [JDK-8319889](https://bugs.openjdk.org/browse/JDK-8319889). I think it's still valuable to integrate this even if these bugs are not resolved yet.
> 
> Thanks,
> Tobias

Tobias Hartmann has updated the pull request incrementally with one additional commit since the last revision:

  Added new helper method

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16597/files
  - new: https://git.openjdk.org/jdk/pull/16597/files/f1b65e52..48b0efd8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16597&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16597&range=02-03

  Stats: 3 lines in 3 files changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/16597.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16597/head:pull/16597

PR: https://git.openjdk.org/jdk/pull/16597