There's no reason to restrict off-heap targets to builtin host Code
objects during serialization. They can also occur e.g. in irregexp
code created by embedded scripts.

Drive-by: unify the list of reloc modes that have a
target_address_address.

Bug: v8:8572,v8:6666
Change-Id: I26dce735463b79677a7b7dcfdb604c5234b5f10b
Reviewed-on: https://chromium-review.googlesource.com/c/1371568Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58194}