RFR: 8353475: Open source two Swing DefaultCaret tests

[Phil Race]

Open source two Swing caret related tests.

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Commit messages:
 - 8353475

Changes: https://git.openjdk.org/jdk/pull/24455/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24455&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353475
  Stats: 134 lines in 2 files changed: 134 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24455.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24455/head:pull/24455

PR: https://git.openjdk.org/jdk/pull/24455