[jdk11u-dev] RFR: 8311585: Add JRadioButtonMenuItem to bug8031573.java

[Andrew Lu]

I backport this for parity with 11.0.23-oracle.

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Commit messages:
 - Backport 4f90abaf17716493bad740dcef76d49f16d69379

Changes: https://git.openjdk.org/jdk11u-dev/pull/2430/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2430&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8311585
  Stats: 24 lines in 1 file changed: 12 ins; 2 del; 10 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2430.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2430/head:pull/2430

PR: https://git.openjdk.org/jdk11u-dev/pull/2430