[lworld+fp16] RFR: 8345053: Add support for FP16 valueOf routines [v2]

[Bhavana Kilambi]

> This patch adds intrinsic support for Float16.valueOf() routines - conversions from int/long/double to half float.

Bhavana Kilambi has updated the pull request incrementally with one additional commit since the last revision:

  Add new microbenchmarks for valueOf() routines

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Changes:
  - all: https://git.openjdk.org/valhalla/pull/1332/files
  - new: https://git.openjdk.org/valhalla/pull/1332/files/342c0304..f7b98148

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1332&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1332&range=00-01

  Stats: 34 lines in 1 file changed: 33 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1332.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1332/head:pull/1332

PR: https://git.openjdk.org/valhalla/pull/1332