Please review this minor cleanup. The related jtreg test, TracePinnedThreads.java/libTracePinnedThreads.c has already been removed by https://github.com/openjdk/jdk/pull/21565 work (for [JDK-8338383](https://bugs.openjdk.org/browse/JDK-8338383)).
------------- Commit messages: - Remove unused BUILD_JDK_JTREG_LIBRARIES_JDK_LIBS_libTracePinnedThreads. Changes: https://git.openjdk.org/jdk/pull/23482/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23482&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8349513 Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/23482.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/23482/head:pull/23482 PR: https://git.openjdk.org/jdk/pull/23482
