[jdk11u-dev] RFR: 8299296: Write a test to verify the components selection sends ItemEvent

[Victor Rudometov]

Backport of https://bugs.openjdk.org/browse/JDK-8299296

Clean backport. 
Parity with 17.0.8-oracle and 11.0.20-oracle
Low risk, new test. 
Test passes on macOS and linux

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Commit messages:
 - Backport 5ae6de859d472d107cdf642c417c6d2f1c74e5db

Changes: https://git.openjdk.org/jdk11u-dev/pull/1701/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1701&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299296
  Stats: 130 lines in 1 file changed: 130 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1701.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1701/head:pull/1701

PR: https://git.openjdk.org/jdk11u-dev/pull/1701