RFR: 8333840: C2 SuperWord: wrong result for MulAddS2I when inputs permuted [v4]

[Emanuel Peter]

> This is an older bug, I discovered it by manual code inspection while refactoring.
> 
> I added some regression tests that produced wrong results.
> 
> You should understand the fix given the comments in the code, if not: tell me how to improve them ;)

Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:

  review changes for Vladimir

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19619/files
  - new: https://git.openjdk.org/jdk/pull/19619/files/24ca79cf..41e98cb5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19619&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19619&range=02-03

  Stats: 6 lines in 1 file changed: 0 ins; 1 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/19619.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19619/head:pull/19619

PR: https://git.openjdk.org/jdk/pull/19619