RFR: JDK-8315876 Open source several Swing CSS related tests [v3]

[Harshitha Onkar]

> Following tests are open sourced as part of this PR.
> 
> 1. test/jdk/javax/swing/text/html/CSS/bug4174871.java
> 2. test/jdk/javax/swing/text/html/CSS/bug4174874.java
> 3. test/jdk/javax/swing/text/html/CSS/bug4284162.java
> 4. test/jdk/javax/swing/text/html/CSS/bug4764897.java
> 5. test/jdk/javax/swing/text/html/HTMLDocument/bug4209280.java

Harshitha Onkar has updated the pull request incrementally with one additional commit since the last revision:

  review changes

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15769/files
  - new: https://git.openjdk.org/jdk/pull/15769/files/4d52fc3d..ba128f03

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15769&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15769&range=01-02

  Stats: 13 lines in 4 files changed: 0 ins; 10 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/15769.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15769/head:pull/15769

PR: https://git.openjdk.org/jdk/pull/15769