This CL reduces the instruction size of Array.prototype.every and some
by ~20%. Should performance allow it we could do the same for other
array builtins. We attach a boolean to the FastJSArrayWitness that
remembers if it's dealing with a FixedArray or a FixedDoubleArray.
We have to check this in the loop, but it is likely that reduced
code size more than pays for the extra check, since the loop will
be dominated by the call to the users callback function.

BUG: v8:7672
Change-Id: Id3bab2b163d7ba73424250d8bb194712909cd37e
Reviewed-on: https://chromium-review.googlesource.com/c/1484293Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59835}