RFR: 8345432: (ch, fs) Replace anonymous Thread with InnocuousThread

[Brian Burkhalter]

Change internal instances of anonymous `Thread`s to instances of `InnocuousThread`.

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Commit messages:
 - 8345432: (ch, fs) Replace anonymous Thread with InnocuousThread

Changes: https://git.openjdk.org/jdk/pull/22697/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22697&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345432
  Stats: 17 lines in 4 files changed: 5 ins; 6 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/22697.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22697/head:pull/22697

PR: https://git.openjdk.org/jdk/pull/22697