RFR: 8306850: Open source AWT Model related tests

[Abhishek Kumar]

This PR is to open source Modal related AWT tests.

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Commit messages:
 - Open source Modal AWT tests

Changes: https://git.openjdk.org/jdk/pull/13676/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13676&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306850
  Stats: 1053 lines in 6 files changed: 1053 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/13676.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13676/head:pull/13676

PR: https://git.openjdk.org/jdk/pull/13676