RFR: JDK-8315824: Open source several Swing Text/HTML related tests

[Harshitha Onkar]

This PR open sources few Swing Text/HTML related tests.

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Commit messages:
 - extra spacing
 - Text/HTML tests

Changes: https://git.openjdk.org/jdk/pull/15675/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15675&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315824
  Stats: 490 lines in 6 files changed: 490 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15675.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15675/head:pull/15675

PR: https://git.openjdk.org/jdk/pull/15675