RFR: 8373724: Assertion failure in TestSignumVector.java with UseAPX [v3]

[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 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' of http://github.com/openjdk/jdk into JDK-8373724
 - 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/bc86d54d..2a63c92b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28999&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28999&range=01-02

  Stats: 2683 lines in 1256 files changed: 410 ins; 251 del; 2022 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