RFR: 8316149: Open source several Swing JTree JViewport KeyboardManager tests [v2]

[Damon Nguyen]

> These are the tests being converted:
> 
> javax/swing/JTree/4696499/bug4696499.java
> javax/swing/JTree/5039542/bug5039542.java
> javax/swing/JViewport/4546474/bug4546474.java
> javax/swing/JViewport/4677611/bug4677611.java
> javax/swing/KeyboardManager/4345798/bug4345798.java

Damon Nguyen has updated the pull request incrementally with one additional commit since the last revision:

  Review comments changes

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15802/files
  - new: https://git.openjdk.org/jdk/pull/15802/files/2f71c4d4..ba7fc98b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15802&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15802&range=00-01

  Stats: 94 lines in 5 files changed: 9 ins; 49 del; 36 mod
  Patch: https://git.openjdk.org/jdk/pull/15802.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15802/head:pull/15802

PR: https://git.openjdk.org/jdk/pull/15802