In GetOwnFastDataPropertyFromHeap, we read a property value
then compare it with the expected representation. We already
had code to bail out of that particular optimization if there
was a mismatch, however it missed the case of expected
representation being a HeapObject, and when a Smi value was found.

The fix is to use the excellent pre-existing method
Object::FitsRepresentation() to make this check. Thusly, all
cases are handled.

Bug: chromium:1225607, v8:7790
Change-Id: I7d9b1b7722d9691cf5427f8456a6deb466dda0d3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3008218
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75587}