Fix gcc static analyzer warning. It was introduced by [JDK-8324868](https://bugs.openjdk.org/browse/JDK-8324868) early last year. For the most part the fix is to revert the relevant [JDK-8324868](https://bugs.openjdk.org/browse/JDK-8324868) changes, except for leaving in the replacement of calling findThread() with instead calling findRunningThread().
Ran all svc tier2 and tier5 tests. ------------- Commit messages: - fix gcc static analyzer warning Changes: https://git.openjdk.org/jdk/pull/27378/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27378&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8361955 Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 mod Patch: https://git.openjdk.org/jdk/pull/27378.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/27378/head:pull/27378 PR: https://git.openjdk.org/jdk/pull/27378
