RFR: 8284281: [Accessibility] [Win] [Narrator] Exceptions with TextArea & TextField when deleted last char [v2]

[Ambarish Rapte]

> Issue:
> When Narrator is running, 
> 1. Deleting last character from `TextField` throws `IllegalArgumentException`, and 
> 2. Deleting last character from `TextArea` throws `NPE`.
> 
> Fix:
> When character is deleted, we receive an offset larger by one than the current text length. This scenario needs to be handled correctly.
> The change in `Text.java` fixes the NPE with TextArea, and,
> The change in `WinTextRangeProvider.java` fixes the IllegalArgumentException with TextField.
> 
> To observe the issue.
> 1. Run any program with TextField and/or TextArea
> 3. Launch Windows Narrator
> 4. Delete the last character from TextField / TextArea
> 5. Observe the related Exception

Ambarish Rapte has updated the pull request incrementally with one additional commit since the last revision:

  change the fix for TextArea Exception

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/884/files
  - new: https://git.openjdk.org/jfx/pull/884/files/18635969..64375399

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=884&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=884&range=00-01

  Stats: 3 lines in 2 files changed: 2 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/884.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/884/head:pull/884

PR: https://git.openjdk.org/jfx/pull/884