Make the hash map test run faster by doing less work

test/cctest/test-hashmap.cc

 // Copyright 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 153 matching lines @@
         CHECK(set.Present(y));
       }
       y = y * factor + offset;
     }
   }
   CHECK_EQ(0, set.occupancy());
 }
 
 
 TEST(Set) {
-  TestSet(Hash, 1000);
-  TestSet(CollisionHash, 100);
+  TestSet(Hash, 100);
+  TestSet(CollisionHash, 50);
 }