Port HammingDistance_NEON 32 bit code to 64 bit
Port HammingDistance_NEON 32 bit code to 64 bit

The 32 bit version of HammingDistance_NEON accumulates
using vertical add and paired adds, which takes 3 instructions
instead of 4.
The instructions are also portable between 32 and 64 bit.

Was BenchmarkHammingDistance_Opt (105 ms)
Now BenchmarkHammingDistance_Opt (90 ms)

TBR=kjellander@chromium.org
BUG=libyuv:701
TEST=BenchmarkHammingDistance

BenchmarkHammingDistance_Opt (90 ms)

Change-Id: If9e621e0bd2fe2492a1532056f8a1b451ba53d7e
Reviewed-on: https://chromium-review.googlesource.com/526365
Reviewed-by: Frank Barchard <52415189a3f67d375195cbbb6fdb1f1759498e57@google.com>
Commit-Queue: Frank Barchard <52415189a3f67d375195cbbb6fdb1f1759498e57@google.com>

lemenkov/libyuv,lemenkov/libyuv,lemenkov/libyuv,lemenkov/libyuv