RFR: 8347359: RichTextArea API Tests [v10]

[Andy Goryachev]

> Additional RichTextArea API tests.

Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:

  review comments

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1677/files
  - new: https://git.openjdk.org/jfx/pull/1677/files/4f07d5f2..8d3f3ecd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1677&range=09
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1677&range=08-09

  Stats: 16 lines in 1 file changed: 13 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/1677.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1677/head:pull/1677

PR: https://git.openjdk.org/jfx/pull/1677