This requires honoring the instance size of the object stored in the
map for JSObject. To do this, allocation is now split into two
instrinsics, one that calculates the base size of the allocated object
(%GetAllocationBaseSize) and one that actually allocates (%Allocate).

In the process, remove objects.tq, which only existed to contain a
macro to fetch the default JSObject map, which is functionality that
is now in the JSObject class constructor.

Bug: v8:7793
Change-Id: I426a7943aac67eacad46d4ff39f5c821489a04bc
Reviewed-on: https://chromium-review.googlesource.com/c/1426959
Commit-Queue: Daniel Clifford <danno@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59052}