This function was removed when clang started introducing alignment hints
which caused the 32 bit vld1_lane_u32/vst1_lane_u32 to fail:
https://llvm.org/bugs/show_bug.cgi?id=24421
The load has been rendered safe with an implementation ~indiscernible
performance-wise that uses _u8 and over-reads just a touch.
The store, when unaligned, has a version that is ~25% slower but safe
when xoffset = 0 (second pass filter only). When the first pass filter
(or both) are in play, the new version is almost identical in speed.
Worst case performance (both filters, unaligned stores) is roughly 3-4x
faster than C.
BUG=webm:817
BUG=webm:1273
Change-Id: I1e490e94453e0872151fe0dafb05557463f6247d