... in order to avoid Code <-> CodeT conversions in builtins.
This CL changes the meaning of RelocInfo::CODE_TARGET which now expects
CodeT objects as a code target.

In order to reduce code churn this CL makes BUILTIN_CODE and friends
return CodeT instead of Code. In the follow-up CLs BUILTIN_CODET and
friends will be removed.

Bug: v8:11880
Change-Id: Ib8f60973e55c60fc62ba84707471da388f8201b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3338483Reviewed-by: Patrick Thier <pthier@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78393}