fix for ubsan on unittest.h fastrand()

unit_test/unit_test.h

 /*
  *  Copyright 2011 The LibYuv Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS. All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 37 matching lines @@
 }
 #else
 static inline double get_time() {
   struct timeval t;
   struct timezone tzp;
   gettimeofday(&t, &tzp);
   return t.tv_sec + t.tv_usec * 1e-6;
 }
 #endif
 
-extern int fastrand_seed;
+extern unsigned int fastrand_seed;
 inline int fastrand() {
-  fastrand_seed = fastrand_seed * 214013 + 2531011;
-  return (fastrand_seed >> 16) & 0xffff;
+  fastrand_seed = fastrand_seed * 214013u + 2531011u;
+  return static_cast<int>((fastrand_seed >> 16) & 0xffff);
 }
 
 static inline void MemRandomize(uint8* dst, int64 len) {
   int64 i;
   for (i = 0; i < len - 1; i += 2) {
     *reinterpret_cast<uint16*>(dst) = fastrand();
     dst += 2;
   }
   for (; i < len; ++i) {
     *dst++ = fastrand();
@@ skipping 72 matching lines @@
   int benchmark_iterations_;  // Default 1. Use 1000 for benchmarking.
   int benchmark_width_;  // Default 1280.  Use 640 for benchmarking VGA.
   int benchmark_height_;  // Default 720.  Use 360 for benchmarking VGA.
   int benchmark_pixels_div256_;  // Total pixels to benchmark / 256.
   int benchmark_pixels_div1280_;  // Total pixels to benchmark / 1280.
   int disable_cpu_flags_;  // Default 1.  Use -1 for benchmarking.
   int benchmark_cpu_info_;  // Default -1.  Use 1 to disable SIMD.
 };
 
 #endif  // UNIT_TEST_UNIT_TEST_H_  NOLINT