RFR: 8283726: x86_64 intrinsics for compareUnsigned method in Integer and Long [v3]

[Quan Anh Mai]

> Hi,
> 
> This patch implements intrinsics for `Integer/Long::compareUnsigned` using the same approach as the JVM does for long and floating-point comparisons. This allows efficient and reliable usage of unsigned comparison in Java, which is a basic operation and is important for range checks such as discussed in #8620 .
> 
> Thank you very much.

Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:

  add comparison for direct value of compare

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9068/files
  - new: https://git.openjdk.org/jdk/pull/9068/files/b5627135..0ab881ac

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9068&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9068&range=01-02

  Stats: 18 lines in 2 files changed: 16 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9068.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9068/head:pull/9068

PR: https://git.openjdk.org/jdk/pull/9068