[vectorIntrinsics+mask] RFR: 8272100: VectorAPI: modify existing implementation of masked neg and not operation.

[Jatin Bhateja]

- Masked NEG/NOT operations can be implemented using existing masked operations instead of emitting an explicit vector blend after the operation. 
- Changes shows around 1.3-1.5X gain when merged with X86 backend changes for masking operations. https://github.com/openjdk/panama-vector/pull/99

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Commit messages:
 - 8272100: changing file permissions.
 - 8272100: VectorAPI: modify existing implementation of masked neg and not operation.

Changes: https://git.openjdk.java.net/panama-vector/pull/108/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=108&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8272100
  Stats: 20 lines in 5 files changed: 10 ins; 0 del; 10 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/108.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/108/head:pull/108

PR: https://git.openjdk.java.net/panama-vector/pull/108