instead of Object* (which is deprecated) or ObjectPtr (which is
unsuitable for cases where we need to control the ABI exactly).
Callers in generated code expect a plain tagged value, so return
precisely that. Same for C++ Builtins.

Bug: v8:3770
Change-Id: Id12f0d9830f7caf2a16aa973b8297f70d65241f5
Reviewed-on: https://chromium-review.googlesource.com/c/1382466Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58334}