RFR: 8378389: Remove AppContext from the Swing RepaintManager [v2]

[Phil Race]

> Remove AppContext from RepaintManager
> 
> Please review the CSR too.

Phil Race has updated the pull request incrementally with one additional commit since the last revision:

  8378389

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29862/files
  - new: https://git.openjdk.org/jdk/pull/29862/files/ddd138cb..515dc6cb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29862&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29862&range=00-01

  Stats: 14 lines in 3 files changed: 2 ins; 7 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/29862.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29862/head:pull/29862

PR: https://git.openjdk.org/jdk/pull/29862