RFR: 8341000: Open source some of the AWT Window tests [v2]

[Jayathirth D V]

> Clean up and open source some of the AWT window tests.
> Automated test `InvalidFocusLostEventTest.java` is verified in our CI also and it passes on all platforms.

Jayathirth D V has updated the pull request incrementally with one additional commit since the last revision:

  Update for review comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21281/files
  - new: https://git.openjdk.org/jdk/pull/21281/files/5985f365..79eab637

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21281&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21281&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/21281.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21281/head:pull/21281

PR: https://git.openjdk.org/jdk/pull/21281