because RelocInfo does not need host Code object for updating pointers to heap
objects embedded into code.

This CL also simplifies typed slot iteration callback signature.

Bug: v8:8518, v8:8262
Change-Id: I59fe9e3b4e9b69e3d87b5449c80bed14e311516f
Reviewed-on: https://chromium-review.googlesource.com/c/1370037Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58136}