RFR: 8345146: [PPC64] Make intrinsic conversions between bit representations of half precision values and floats [v2]

[Martin Doerr]

> PPC64 implementation of [JDK-8289552](https://bugs.openjdk.org/browse/JDK-8289552). I've implemented some more instructions which may be useful in the future.

Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:

  Indentation.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22433/files
  - new: https://git.openjdk.org/jdk/pull/22433/files/b3960683..02e54629

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22433&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22433&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/22433.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22433/head:pull/22433

PR: https://git.openjdk.org/jdk/pull/22433