RFR: 8315606: Open source few swing text/html tests

[Prasanta Sadhukhan]

Few closed swing text/html tests are opensourced

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

Commit messages:
 - 8315606: Open source few swing text/html tests

Changes: https://git.openjdk.org/jdk/pull/15580/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15580&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315606
  Stats: 398 lines in 4 files changed: 398 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15580.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15580/head:pull/15580

PR: https://git.openjdk.org/jdk/pull/15580