RFR: 8345015: Remove unused lookup_time_t_function

[Marc R. Hoffmann]

With JDK-8343785 all usages of this method have been eliminated.

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Commit messages:
 - 8345015: Remove unused lookup_time_t_function

Changes: https://git.openjdk.org/jdk/pull/22383/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22383&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8345015
  Stats: 17 lines in 1 file changed: 0 ins; 17 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/22383.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22383/head:pull/22383

PR: https://git.openjdk.org/jdk/pull/22383