Align structures in quantize test

MACROBLOCKD structures require alignment.

This fixes an issue caught by clang IOC.

Change-Id: Ibb5bcc122f531b4302a87e1144e4feaf46c1de64

test/quantize_test.cc

diff --git a/test/quantize_test.cc b/test/quantize_test.cc
index aaa195a..66d7699 100644
--- a/test/quantize_test.cc
+++ b/test/quantize_test.cc
@@ -69,9 +69,8 @@
     vp8cx_frame_init_quantizer(vp8_comp_);
 
     // Copy macroblockd from the reference to get pre-set-up dequant values.
-    macroblockd_dst_ =
-        reinterpret_cast<MACROBLOCKD *>(
-            vpx_calloc(sizeof(*macroblockd_dst_), 1));
+    macroblockd_dst_ = reinterpret_cast<MACROBLOCKD *>(
+        vpx_memalign(32, sizeof(*macroblockd_dst_)));
     vpx_memcpy(macroblockd_dst_, &vp8_comp_->mb.e_mbd,
                sizeof(*macroblockd_dst_));
     // Fix block pointers - currently they point to the blocks in the reference