Add some unaligned test vectors

Tests resolutions of 8, 10, 16, 18, 32, 34, 64, 66 to exercise the
border conditions, as well as non-SB aligned sizes.

Change-Id: Ie7c2b7860ac3727e23202042f2e86792652912f8
Implement sse2 and ssse3 versions for all sub_pixel_variance sizes.

Overall speedup around 5% (bus @ 1500kbps first 50 frames 4min10 ->
3min58). Specific changes to timings for each function compared to
original assembly-optimized versions (or just new version timings if
no previous assembly-optimized version was available):

sse2   4x4:    99 ->   82 cycles
sse2   4x8:           128 cycles
sse2   8x4:           121 cycles
sse2   8x8:   149 ->  129 cycles
sse2   8x16:  235 ->  245 cycles (?)
sse2  16x8:   269 ->  203 cycles
sse2  16x16:  441 ->  349 cycles
sse2  16x32:          641 cycles
sse2  32x16:          643 cycles
sse2  32x32: 1733 -> 1154 cycles
sse2  32x64:         2247 cycles
sse2  64x32:         2323 cycles
sse2  64x64: 6984 -> 4442 cycles

ssse3  4x4:           100 cycles (?)
ssse3  4x8:           103 cycles
ssse3  8x4:            71 cycles
ssse3  8x8:           147 cycles
ssse3  8x16:          158 cycles
ssse3 16x8:   188 ->  162 cycles
ssse3 16x16:  316 ->  273 cycles
ssse3 16x32:          535 cycles
ssse3 32x16:          564 cycles
ssse3 32x32:          973 cycles
ssse3 32x64:         1930 cycles
ssse3 64x32:         1922 cycles
ssse3 64x64:         3760 cycles

Change-Id: I81ff6fe51daf35a40d19785167004664d7e0c59d
Revert "test_libvpx: disable pthreads in gtest"

This reverts commit 90a9900abb79fabfd44189a959d14ca677c2777a

Seems to break the Mac build:
src/include/gtest/internal/gtest-port.h:1208:: pthread_mutex_lock(&mutex_)failed with error 22
Abort trap: 6

Change-Id: Icbe31161d7c27f1b0a28d33409e7712430bbf0ae
Fix win64 warning.

- size_t vs int.

Change-Id: Ib47ebd932a4b69db9f52a43000bb69d0a96b9134
Merge "Revert "test_libvpx: disable pthreads in gtest""
clean out libvpx-srcs.txt if built

Change-Id: Idfd69e66e8982275eb00d8007a55efd1a4f86a98
Merge "clean out libvpx-srcs.txt if built"
SSE2/SSSE3 optimizations and unit test for sub_pixel_avg_variance().

Encoding of bus @ 1500kbps (first 50 frames) goes from 3min57 to
3min35, i.e. approximately a 10.5% speedup. Note that the SIMD versions
which use a bilinear filter (x_offset & 7 || y_offset & 7) aren't
perfectly interleaved, and can probably be improved further in the
future. I've marked this with a few TODOs/FIXMEs in the code.

Change-Id: I5c9e900c0f0d32e431a50fecae213b510b2549f9
Merge "Implement sse2 and ssse3 versions for all sub_pixel_variance sizes."
rename variables to avoid build error in MSVC

Change-Id: I7960178c95c54d5c4497e44cfc8c493566294b34
Merge "rename variables to avoid build error in MSVC"
Get some speed back for cpuused 1

and remove unused code.

Change-Id: If380440c4450294b5450b7a9eeb94a376846ec01
Merge "Get some speed back for cpuused 1"
Add subtract_block SSE2 version and unit test.

3% faster overall (3min35.0 to 3min28.5).

Change-Id: I5ff8a5c2c91586b6632ca5009ad1ea51ce94af5e
Merge "SSE2/SSSE3 optimizations and unit test for sub_pixel_avg_variance()."
Merge "Add subtract_block SSE2 version and unit test."
Implement SSE2 block_error.

Change vp9_block_error() to return a 64bit error variable, change all
callers to expect a 64bit return value (this will prevent overflows,
which we basically don't check for at all right now). Remove duplicate
block_error() function, which fixed that through truncation. Remove
old (incompatible) mmx/sse2 block_error SIMD versions and replace with
a new one that returns a 64bit value.

Encoding time of first 50 frames of bus @ 1500kbps goes from 3min29 to
3min23, i.e. a 3% overall speedup.

Change-Id: Ib71ac5508b5ee8a80f1753cd85d72df1629abe68
Add missing SECTION .text marker in assembly file.

Fixes a crash on Windows when building with MSVC.

Change-Id: I124ac756a1be55d190fadda5fcc46d23b1445dbf
Removing find_seg_id and using vp9_get_pred_mi_segid instead.

Change-Id: Ia40229903c08f14020e90e94cfdf494aba1be827
variance_test: use REGISTER_STATE_CHECK

Change-Id: Id54ad9a781634f075e990d5bade5be8490959975