RFR: 8322735: C2: minor improvements of bubble sort used in SuperWord::packset_sort

[Denghui Dong]

A minor improvement could be made for bubble sort in SuperWord::packset_sort to reduce the comparison count in bad cases.

See https://en.wikipedia.org/wiki/Bubble_sort

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Commit messages:
 - 8322735: C2: minor improvements of bubble sort used in SuperWord::packset_sort

Changes: https://git.openjdk.org/jdk/pull/17190/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17190&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322735
  Stats: 6 lines in 1 file changed: 0 ins; 1 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/17190.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17190/head:pull/17190

PR: https://git.openjdk.org/jdk/pull/17190