RFR: 8288137: The set of available printers is not updated without application restart [v2]

[Phil Race]

> This fixes the issue that the default printer or set of available printers is fixed from the first call to it in the lifetime of the application.
> Now subsequent calls will check to see if there are changes.
> A manual test is provided for verifying this - it requires you to add/remove printers at the system level to verify anything related to this fix.

Phil Race has updated the pull request incrementally with one additional commit since the last revision:

  8288137

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/817/files
  - new: https://git.openjdk.org/jfx/pull/817/files/0cb60d76..4932450c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=817&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=817&range=00-01

  Stats: 3 lines in 1 file changed: 1 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jfx/pull/817.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/817/head:pull/817

PR: https://git.openjdk.org/jfx/pull/817