<AWT Dev> RFR: 8260931: Implement JEP 382: New macOS Rendering Pipeline [v4]

[Ajit Ghaisas]

> **Description :**
> This is the implementation of [JEP 382 : New macOS Rendering Pipeline](https://bugs.openjdk.java.net/browse/JDK-8238361)
> It implements a Java 2D internal rendering pipeline for macOS using the Apple Metal API.
> The entire work on this was done under [OpenJDK Project - Lanai](http://openjdk.java.net/projects/lanai/)
> 
> We iterated through several Early Access (EA) builds and have reached a stage where it is ready to be integrated to openjdk/jdk. The latest EA build is available at - https://jdk.java.net/lanai/
> 
> A new option -Dsun.java2d.metal=true | True needs to be used to use this pipeline.
> 
> **Testing :**
> This implementation has been tested with the tests present at - [Test Plan for JEP 382: New macOS Rendering Pipeline](https://bugs.openjdk.java.net/browse/JDK-8251396)
> 
> **Note to reviewers :**
> 1) Default rendering pipeline on macOS has not been changed by this PR. OpenGL still stays as the default rendering pipeline and Metal rendering pipeline is optional to choose.
> 
> 2) To apply and test this PR - 
> To enable the metal pipeline you must specify on command line -Dsun.java2d.metal=true (No message will be printed in this case) or -Dsun.java2d.metal=True (A message indicating Metal rendering pipeline is enabled gets printed)

Ajit Ghaisas has updated the pull request incrementally with two additional commits since the last revision:

 - Lanai PR#177 - 8261430 - aghaisas
 - Lanai PR#176 - 8261399 - jdv

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2403/files
  - new: https://git.openjdk.java.net/jdk/pull/2403/files/6044adc0..64173289

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2403&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2403&range=02-03

  Stats: 49 lines in 14 files changed: 0 ins; 43 del; 6 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2403.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2403/head:pull/2403

PR: https://git.openjdk.java.net/jdk/pull/2403