RFR: 8296632: Write a test to verify the content change of TextArea sends TextEvent. [v3]

[ravi gupta]

> This testcase Verify the content changes of a TextArea for the following assertions.
> 
> a. TextListener get invoked when the content of a TextArea gets changed.
> b. TextListener not get invoked during text selection or when Special keys such as Function Keys are pressed.
> 
> 
> Testing:
> Tested using Mach5(20 times per platform) in macos,linux and windows and got all pass.

ravi gupta has updated the pull request incrementally with one additional commit since the last revision:

  8296632: Review fixes.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11052/files
  - new: https://git.openjdk.org/jdk/pull/11052/files/898c2bf3..c5c93e82

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11052&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11052&range=01-02

  Stats: 4 lines in 1 file changed: 0 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/11052.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11052/head:pull/11052

PR: https://git.openjdk.org/jdk/pull/11052