[lworld+fp16] RFR: 8334432: Refine Float16.fma [v5]

[Joe Darcy]

> Adding comments and test cases for Float16.fma.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Add tests for subnromal results.

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Changes:
  - all: https://git.openjdk.org/valhalla/pull/1143/files
  - new: https://git.openjdk.org/valhalla/pull/1143/files/46a84462..32bb73a6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1143&range=04
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1143&range=03-04

  Stats: 11 lines in 1 file changed: 8 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1143.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1143/head:pull/1143

PR: https://git.openjdk.org/valhalla/pull/1143