RFR: 8338694: x86_64 intrinsic for tanh using libm [v7]

[Srinivas Vamsi Parasa]

> The goal of this PR is to implement an x86_64 intrinsic for java.lang.Math.tanh() using libm
> 
> Benchmark (ops/ms) | Stock JDK | Tanh intrinsic | Speedup
> -- | -- | -- | --
> MathBench.tanhDouble | 70900 | 95618 | 1.35x

Srinivas Vamsi Parasa has updated the pull request incrementally with three additional commits since the last revision:

 - Update HyperbolicTests.java
   
   Remove the path to random library
 - update copyright year and remove unused random from HyperbolicTests
 - remove tanh tests in seprate file

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/20657/files
  - new: https://git.openjdk.org/jdk/pull/20657/files/ca3314c5..e908eb44

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20657&range=06
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20657&range=05-06

  Stats: 1640 lines in 2 files changed: 735 ins; 892 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/20657.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20657/head:pull/20657

PR: https://git.openjdk.org/jdk/pull/20657