RFR: 8373724: Assertion failure in TestSignumVector.java with UseAPX [v2]

[Jatin Bhateja]

> Existing demotable instruction patterns for negI/L_rReg_ndd have 'src' as their second operand, this leads to an failure during register biasing. Changing the NDD demotion flags names to encode explicit operand position i.e. **Flag_ndd_demotable_opr1 and Flag_ndd_demotable_opr2** , splitting commutative flag into seperate new flags and fine tuning assertion checks based on new naming convention fixes the issue.
> 
> Failing test test/hotspot/jtreg/compiler/vectorization/TestSignumVector.java passes with the patch.
> 
> Kindly review and share your feedback.
> 
> Best Regards,
> Jatin
> PS: Validation performed using Intel SDE 9.58.

Jatin Bhateja has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  8373724: Assertion failure in TestSignumVector.java with UseAPX

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28999/files
  - new: https://git.openjdk.org/jdk/pull/28999/files/b75d280f..bc86d54d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28999&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28999&range=00-01

  Stats: 3 lines in 1 file changed: 2 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/28999.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28999/head:pull/28999

PR: https://git.openjdk.org/jdk/pull/28999