[x265] [PATCH 276 of 307] x86: AVX512 fix testbench crash for ssd_s aligned

[mythreyi at multicorewareinc.com]

# HG changeset patch
# User Jayashree
# Date 1514886668 -19800
#      Tue Jan 02 15:21:08 2018 +0530
# Node ID 80775bda5ec16735e7b1de97dedeb7f7ed391c8f
# Parent  47fd272d3c7002b5a84067a818ca4ae1c61276c1
x86: AVX512 fix testbench crash for ssd_s aligned

diff -r 47fd272d3c70 -r 80775bda5ec1 source/test/pixelharness.cpp
--- a/source/test/pixelharness.cpp	Fri Dec 29 17:38:37 2017 +0530
+++ b/source/test/pixelharness.cpp	Tue Jan 02 15:21:08 2018 +0530
@@ -275,7 +275,7 @@
     for (int i = 0; i < ITERS; i++)
     {
                // NOTE: stride must be multiple of 16, because minimum block is 4x4
-        int stride = (STRIDE + (rand() % STRIDE)) & ~15;
+        int stride = STRIDE;
         sse_t cres = ref(sbuf1 + j, stride);
         sse_t vres = (sse_t)checked(opt, sbuf1 + j, (intptr_t)stride);