RFR: 8273617: UninitializedDisplayModeChangeTest.java times out on macOS 12 [v4]

[Prasanta Sadhukhan]

> Test used to timeout even though it seems the test passed..Increased the timeout to a safe value as sometimes it shows elapsed time to timeout > 300secs in macOS in CI and also ensured the wait-time for child process to execute the test is not been waiting endlessly.
> Also ensured the original display mode is resetted after the test to prevent affecting following tests.
> 
> Tried 100 iterations of the fix on all platforms which is ok

Prasanta Sadhukhan has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'master' of https://git.openjdk.java.net/jdk into JDK-8273617
 - Remove displayMode reset
 - EDT fix, timeout reduced
 - 8273617: UninitializedDisplayModeChangeTest.java times out on macOS 12

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27365/files
  - new: https://git.openjdk.org/jdk/pull/27365/files/03c99829..0e6416e5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27365&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27365&range=02-03

  Stats: 127485 lines in 998 files changed: 115047 ins; 8214 del; 4224 mod
  Patch: https://git.openjdk.org/jdk/pull/27365.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27365/head:pull/27365

PR: https://git.openjdk.org/jdk/pull/27365