[jdk17u-dev] RFR: 8296934: Write a test to verify whether Undecorated Frame can be iconified or not

[Goetz Lindenmaier]

I backport this for parity with 17.0.8-oracle.

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Commit messages:
 - Backport 7845b0d7b4193688448b7bf0c427df4976d302e5

Changes: https://git.openjdk.org/jdk17u-dev/pull/1333/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1333&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296934
  Stats: 200 lines in 1 file changed: 200 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1333.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1333/head:pull/1333

PR: https://git.openjdk.org/jdk17u-dev/pull/1333