For holey Smi and double source arrays, we would go to the general
case, which is much slower than before. We already check that there
are no prototype chain changes in IterableToListCanBeElided, and
there is no JS-code run between that check and the copying of the
elements, so we can safely check for the hole and convert it to
undefined, which is then converted to 0/NaN appropriately for the
given TypedArray.

Bug: chromium:713570,chromium:711275
Change-Id: I5b21c915907d71eebb73b7b1eea8eb58b4a5436d
Reviewed-on: https://chromium-review.googlesource.com/485520
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44899}