RFR: 8378389: Remove AppContext from the Swing RepaintManager [v3]

[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/515dc6cb..0be12b77

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29862&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29862&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 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