Fix more warnings on linux

Source/wtf/HashMapTest.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 37 matching lines @@
     ASSERT_TRUE(map.begin() == begin);
     ASSERT_TRUE(begin != map.end());
     ASSERT_TRUE(map.end() != begin);
     ASSERT_FALSE(begin != map.begin());
     ASSERT_FALSE(map.begin() != begin);
     ASSERT_FALSE(begin == map.end());
     ASSERT_FALSE(map.end() == begin);
 }
 
 struct TestDoubleHashTraits : HashTraits<double> {
-    static const int minimumTableSize = 8;
+    static const unsigned minimumTableSize = 8;
 };
 
 typedef HashMap<double, int64_t, DefaultHash<double>::Hash, TestDoubleHashTraits> DoubleHashMap;
 
 static int bucketForKey(double key)
 {
     return DefaultHash<double>::Hash::hash(key) & (TestDoubleHashTraits::minimumTableSize - 1);
 }
 
 TEST(WTF, DoubleHashCollisions)
@@ skipping 86 matching lines @@
     ASSERT_EQ(1, map.get(ptr));
 
     ptr.clear();
     ASSERT_FALSE(isDeleted);
 
     map.clear();
     ASSERT_TRUE(isDeleted);
 }
 
 } // namespace