RFR: 8376113: PPC64: Implement special MachNodes for floating point Min / Max [v5]

[David Briemann]

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

David Briemann has updated the pull request incrementally with two additional commits since the last revision:

 - update copyright headers for JDK-8375536
 - update copyright headers

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29361/files
  - new: https://git.openjdk.org/jdk/pull/29361/files/4621017d..7201aa5b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29361&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29361&range=03-04

  Stats: 9 lines in 6 files changed: 0 ins; 0 del; 9 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