[jdk17u-dev] RFR: 8286447: [Linux] AWT should start in Headless mode if headful AWT library not installed

[Ludovic Henry]

Backport applied cleanly.

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Commit messages:
 - Backport aa5062584c5a17d1ad21e31ce3f4768f6a5edbc8

Changes: https://git.openjdk.org/jdk17u-dev/pull/2150/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=2150&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8286447
  Stats: 35 lines in 1 file changed: 30 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/2150.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/2150/head:pull/2150

PR: https://git.openjdk.org/jdk17u-dev/pull/2150