RFR: 8333840: C2 SuperWord: wrong result for MulAddS2I when inputs permuted [v6]

[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:

  Apply suggestions from code review
  
  Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19619/files
  - new: https://git.openjdk.org/jdk/pull/19619/files/2155d18b..03039e06

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19619&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19619&range=04-05

  Stats: 4 lines in 1 file changed: 0 ins; 1 del; 3 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