[jdk21u-dev] RFR: 8352687: Opensource few JInternalFrame and JTextField tests

[Satyen Subramaniam]

Backporting JDK-8352687: Opensource few JInternalFrame and JTextField tests. Adds two JInternalFrame tests and two JTextField tests. Ran GHA Sanity Checks and new tests directly. Patch is clean. Backporting for parity with Oracle.

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Commit messages:
 - Merge branch 'openjdk:master' into 8352687
 - Backport f955a8cbd2d1233af7f7e4b4e4bfcdbb5a8cacae

Changes: https://git.openjdk.org/jdk21u-dev/pull/2444/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2444&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8352687
  Stats: 349 lines in 4 files changed: 349 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2444.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2444/head:pull/2444

PR: https://git.openjdk.org/jdk21u-dev/pull/2444