- Remove redundant instruction from I16x8Splat
 - Force F32x4Splat to use movss, as using MacroAssembler can mix SSE/AVX
 instructions

Bug: v8:6020
Change-Id: I781c22adecf892a79b6a38c3d83fc4022f9067de
Reviewed-on: https://chromium-review.googlesource.com/898429Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51123}