[jdk21u-dev] RFR: 8327754: Convert javax/swing/JPopupMenu/7160604/bug7160604.java applet to main

[Goetz Lindenmaier]

I backport this for parity with 21.0.9-oracle

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

Commit messages:
 - Backport 628e7702746ed4cc899d9727432b64c701533eb3

Changes: https://git.openjdk.org/jdk21u-dev/pull/1890/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1890&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327754
  Stats: 237 lines in 3 files changed: 112 ins; 125 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1890.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1890/head:pull/1890

PR: https://git.openjdk.org/jdk21u-dev/pull/1890