[vectorIntrinsics] RFR: 8283413: Add C2 mid-end and x86 back-end implementation for bit REVERSE operation

[Jatin Bhateja]

Hi All,

Patch includes following changes:-
- New C2 IR nodes to support VectorOperations.REVERSE operation.
- X86 backend implementation for targets supporting AVX2, AVX512 and GFNI features.

Please find below the performance data of Vector API JMH micros:-

System Configuration:
ICX: Intel(R) Xeon(R) Platinum 8380 CPU @ 2.30GHz (40C 2S)
CLX: Intel(R) Xeon(R) Platinum 8280 CPU @ 2.70GHz (28C 2S)

![image](https://user-images.githubusercontent.com/59989778/159196997-fd1ae2ad-37ee-4294-9928-5764707bb456.png)



Kindly review and share your feedback.

Regards,
Jatin

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Commit messages:
 - 8283413: Add C2 mid-end and x86 back-end implementation for bit REVERSE operation

Changes: https://git.openjdk.java.net/panama-vector/pull/182/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=182&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283413
  Stats: 426 lines in 17 files changed: 420 ins; 2 del; 4 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/182.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/182/head:pull/182

PR: https://git.openjdk.java.net/panama-vector/pull/182