RFR: 8297489: Write a test to verify the content change of TextField sends TextEvent [v3]

[ravi gupta]

> This testcase Verify the content changes of a TextField for the following assertions.
> 
> a. TextListener get invoked when the content of a TextField 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:

  8297489: Review fixes

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11326/files
  - new: https://git.openjdk.org/jdk/pull/11326/files/dee88683..a0fc7073

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11326&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11326&range=01-02

  Stats: 3 lines in 1 file changed: 1 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11326.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11326/head:pull/11326

PR: https://git.openjdk.org/jdk/pull/11326