[jdk17u-dev] RFR: 8273043: [TEST_BUG] Automate NimbusJTreeSelTextColor.java

[Goetz Lindenmaier]

I backport this for parity with 17.0.6-oracle.

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Commit messages:
 - Backport 270a9d929307dce52e6961e57492c03a633ed044

Changes: https://git.openjdk.org/jdk17u-dev/pull/679/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=679&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8273043
  Stats: 144 lines in 1 file changed: 43 ins; 53 del; 48 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/679.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/679/head:pull/679

PR: https://git.openjdk.org/jdk17u-dev/pull/679