RFR: 8322077: Add Ideal transformation: (~a) | (~b) => ~(a & b) [v6]

[Zhiqiang Zang]

> Hello,
> 
> (~a) | (~b) => ~(a & b) is a widely seen pattern, for example it is implemented for LLVM [here](https://github.com/llvm/llvm-project/blob/397f1ce9efb4eea1ee10fe4833f733b8c7abd878/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp#L1617C28-L1617C28); however it is missing in current implementation of hotspot. This pull request adds this transformation and associated tests.
> 
> Thanks.

Zhiqiang Zang has updated the pull request incrementally with one additional commit since the last revision:

  remove unused code from tests.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16334/files
  - new: https://git.openjdk.org/jdk/pull/16334/files/154c69e5..f7e57ce4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16334&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16334&range=04-05

  Stats: 2 lines in 2 files changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/16334.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16334/head:pull/16334

PR: https://git.openjdk.org/jdk/pull/16334