RFR: 8376113: PPC64: Implement special MachNodes for floating point Min / Max [v6]

[David Briemann]

> Add mach nodes MinF, MaxF, MinD, MaxD for PPC.

David Briemann has updated the pull request incrementally with one additional commit since the last revision:

  more copyright updates..

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29361/files
  - new: https://git.openjdk.org/jdk/pull/29361/files/7201aa5b..6a412777

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29361&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29361&range=04-05

  Stats: 5 lines in 4 files changed: 2 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/29361.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29361/head:pull/29361

PR: https://git.openjdk.org/jdk/pull/29361