This CL migrates JSFunction's code accessors to CodeT.

Bug: v8:11880
Change-Id: I8cf367eb79cc1d59548dd4f3e18c010f76f101cb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3330466Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78365}