<i18n dev> RFR: JDK-8303950: [macos]Translucent Windows Flicker on Repaint [v5]

[Jeremy]

> I'm confident about the new test case for this ticket, but the resolution is more invasive than I'd like. (It works, though.)
> 
> In short:
> This introduces a new RenderingHint (in SunHints) to bypass the call in Window to `gg2d.fillRect(0, 0, getWidth(), getHeight());`
> 
> I left more detailed notes here about the proposed resolution:
> https://github.com/openjdk/jdk/commit/1991fdac5dbf76ddaf73cc78a9f7c38370c9674c
> 
> I'm open to suggestions if anyone has a more elegant proposal to prevent the monitor from refreshing too soon?

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

 - 8303950: adding opaque white window under test windows
   
   Since the bottom two windows are translucent: it will help safeguard test results if they're positioned above an opaque white background.
   
   Also adding a couple of text lines to the windows to help explain why they rendered the way they did.
 - 8303950: rolling back unnecessary
   
   This is should have been part of 6a3a9b42bb705273e1ed9b1de0d04370e69c43ca, which rolled back 1991fdac5dbf76ddaf73cc78a9f7c38370c9674c

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/12993/files
  - new: https://git.openjdk.org/jdk/pull/12993/files/bd81761a..c0d80dc6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12993&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12993&range=03-04

  Stats: 39 lines in 2 files changed: 36 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12993.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/12993/head:pull/12993

PR: https://git.openjdk.org/jdk/pull/12993