[jdk25] RFR: 8358526: Clarify behavior of java.awt.HeadlessException constructed with no-args

[Phil Race]

This needs to be backported

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

Commit messages:
 - Backport 81985d422d3a433c1248deec18e4fd9b9f780c2c

Changes: https://git.openjdk.org/jdk/pull/25921/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25921&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358526
  Stats: 52 lines in 2 files changed: 51 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25921.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25921/head:pull/25921

PR: https://git.openjdk.org/jdk/pull/25921