[jdk11u-dev] RFR: 8306372: Open source AWT CardLayout and Checkbox tests

[Andrew Lu]

I backport this for parity with 11.0.21-oracle.

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

Commit messages:
 - Backport 781d6d793ad4cecb774bcbcb362c726779408ffd

Changes: https://git.openjdk.org/jdk11u-dev/pull/2112/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=2112&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8306372
  Stats: 364 lines in 6 files changed: 364 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/2112.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/2112/head:pull/2112

PR: https://git.openjdk.org/jdk11u-dev/pull/2112