RFR: 8340985: Open source some Desktop related tests [v4]

[Alexander Zuev]

> Clean up and open source five regression tests related to java.awt.Desktop component.

Alexander Zuev has updated the pull request incrementally with one additional commit since the last revision:

  Restore headful key

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Changes:
  - all: https://git.openjdk.org/jdk/pull/21321/files
  - new: https://git.openjdk.org/jdk/pull/21321/files/fe67e048..2a767e4f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=21321&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21321&range=02-03

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21321.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21321/head:pull/21321

PR: https://git.openjdk.org/jdk/pull/21321