RFR: 8311922: [macOS] right-Option key fails to generate release event

[Damon Nguyen]

Previously, a new key combination involving the option key was added to Aqua LAF for JTextAreas. In doing so, some code was removed that created this regression. The regression caused the right option key on Mac OS to incorrectly show another KeyPressed event instead of a KeyReleased event when pressing and releasing the key. Additionally, the location of the key was 'standard' instead of 'right'. Adding back the key mask and its following code resolves the issue and doesn't cause any other CI tests to fail.

The headful test included displays the key events as they're pressed. After the changes, the test correctly shows the right option key's KeyPressed and KeyReleased events and shows the location as 'right'.

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

Commit messages:
 - Add back key mask and logic for right option. Add new test

Changes: https://git.openjdk.org/jdk/pull/15432/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15432&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8311922
  Stats: 197 lines in 2 files changed: 197 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15432.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15432/head:pull/15432

PR: https://git.openjdk.org/jdk/pull/15432