RFR: 8306137: Open source several AWT ScrollPane related tests [v2]

[Tejesh R]

> Open source few AWT ScrollPane related tests.

Tejesh R has updated the pull request incrementally with two additional commits since the last revision:

 - Updated based on Review Comments
 - Updated based on Review Comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13621/files
  - new: https://git.openjdk.org/jdk/pull/13621/files/e932bed3..ffad753e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13621&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13621&range=00-01

  Stats: 757 lines in 10 files changed: 369 ins; 377 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/13621.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13621/head:pull/13621

PR: https://git.openjdk.org/jdk/pull/13621