Fix MSVC compiler warning after commit r16612.

test/cctest/test-strtod.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 430 matching lines @@
   lo = 18273 * (lo & 0xFFFF) + (lo >> 16);
   return (hi << 16) + (lo & 0xFFFF);
 }
 
 
 static const int kBufferSize = 1024;
 static const int kShortStrtodRandomCount = 2;
 static const int kLargeStrtodRandomCount = 2;
 
 TEST(RandomStrtod) {
-  srand(time(NULL));
+  srand(static_cast<unsigned int>(time(NULL)));
   char buffer[kBufferSize];
   for (int length = 1; length < 15; length++) {
     for (int i = 0; i < kShortStrtodRandomCount; ++i) {
       int pos = 0;
       for (int j = 0; j < length; ++j) {
         buffer[pos++] = rand() % 10 + '0';
       }
       int exponent = DeterministicRandom() % (25*2 + 1) - 25 - length;
       buffer[pos] = '\0';
       Vector<const char> vector(buffer, pos);
       double strtod_result = Strtod(vector, exponent);
       CHECK(CheckDouble(vector, exponent, strtod_result));
     }
   }
   for (int length = 15; length < 800; length += 2) {
     for (int i = 0; i < kLargeStrtodRandomCount; ++i) {
       int pos = 0;
       for (int j = 0; j < length; ++j) {
         buffer[pos++] = rand() % 10 + '0';
       }
       int exponent = DeterministicRandom() % (308*2 + 1) - 308 - length;
       buffer[pos] = '\0';
       Vector<const char> vector(buffer, pos);
       double strtod_result = Strtod(vector, exponent);
       CHECK(CheckDouble(vector, exponent, strtod_result));
     }
   }
 }