Added a parameter to Object::FitsRepresentation() to disallow coercion.
Normally, when we ask if a Smi can "fit" into a Double representation
we'd answer yes, because the Smi can be converted to a HeapNumber.
However, from the compilers perspective, the object is found in a
field with a particular representation. In this case, finding a
Smi in a field with representation Double means something is awry.
Therefore, it's useful for the compiler to be able to ask if
the object fits the field without coercion.

Bug: chromium:1227324, v8:7790
Change-Id: I12033736030d904ef9c29516c07999600a5f508a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3015570
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75706}