RFR: 8332416: Add more font selection options to Font2DTest

[Phil Race]

Enhance Font2DTest as follows

- Add main menu Radio Button options so that you select the font to use as either
- (1) Font Family  + Style (as now)
- (2) Font Family + Menu of all members of the Family, replacing the Style
- (3) List of all fontnames - which can still be adjusted by Style if you want.
The default is (1) so nothing looks different except that I updated the UI to use Nimbus instead of Metal.

There's new code to gather these ways of referencing the fonts.
Also changes were needed for the "Save/Load" options to include the new UI state and font settings.

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Commit messages:
 - 8332416

Changes: https://git.openjdk.org/jdk/pull/19273/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19273&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8332416
  Stats: 459 lines in 2 files changed: 407 ins; 12 del; 40 mod
  Patch: https://git.openjdk.org/jdk/pull/19273.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19273/head:pull/19273

PR: https://git.openjdk.org/jdk/pull/19273