This correctly types values loaded via {LoadElement} nodes from arrays
of HOLEY_DOUBLE_ELEMENTS elements kind as {Type::NumberOrHole}. Even
though "the hole" is still encoded as a tagged NaN, the type system
still needs to consider it as a potential hole value.

R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-crbug-736575
BUG=chromium:736575

Change-Id: Ib869284900a4affb2ddaa1d2a96df9443dba6921
Reviewed-on: https://chromium-review.googlesource.com/567180Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46620}