RFR: 8289552: Make intrinsic conversions between bit representations of half precision values and floats [v9]

[Smita Kamath]

> 8289552: Make intrinsic conversions between bit representations of half precision values and floats

Smita Kamath has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision:

 - Merge branch 'master' of https://git.openjdk.java.net/jdk into JDK-8289552
 - Addressed review comments
 - Added missing parantheses
 - Addressed review comments, updated microbenchmark
 - Updated copyright comment
 - Updated test cases as per review comments
 - Addressed review comments, updated test cases and microbenchmark
 - Added a jmh microbenchmark
 - Intrinsic conversions between halffloat and floats

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9781/files
  - new: https://git.openjdk.org/jdk/pull/9781/files/6b828e60..bd55803a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9781&range=08
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9781&range=07-08

  Stats: 162166 lines in 2652 files changed: 77056 ins; 68233 del; 16877 mod
  Patch: https://git.openjdk.org/jdk/pull/9781.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9781/head:pull/9781

PR: https://git.openjdk.org/jdk/pull/9781