Pass heap directly into RelocInfo::set_target_object and its calling
functions to avoid HeapObject::GetHeap().

Bug: v8:7786
Change-Id: I516b8b2d80a86ba5aba70160290e78354bb9a7b8
Reviewed-on: https://chromium-review.googlesource.com/1080548Reviewed-by: Yang Guo <yangguo@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53469}