RFR: 8261553: Efficient mask generation using BMI2 BZHI instruction [v2]

[Jatin Bhateja]

> BMI2 BHZI instruction can be used to optimize the instruction sequence
> used for mask generation at various place in array copy stubs and partial in-lining for small copy operations.

Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:

  8261553: Adding BMI2 missing check for partial in-lining.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2522/files
  - new: https://git.openjdk.java.net/jdk/pull/2522/files/38495aec..84c9c2da

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2522&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2522&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2522.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2522/head:pull/2522

PR: https://git.openjdk.java.net/jdk/pull/2522