Force GC before executing unbox double arrays test to avoid timeouts.

test/mjsunit/unbox-double-arrays.js

 // Copyright 2012 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 334 matching lines @@
                       Infinity,
                       -Infinity,
                       expected_array_value(7));
 
   assertTrue(%GetOptimizationStatus(test_various_stores) != 2);
 
   // Make sure that we haven't converted from fast double.
   assertTrue(%HasFastDoubleElements(large_array));
 }
 
+// Force gc here to start with a clean heap if we repeat this test multiple
+// times.
+gc();
 testOneArrayType(make_object_like_array);
 testOneArrayType(Array);
 
 var large_array = new Array(large_array_size);
 force_to_fast_double_array(large_array);
 assertTrue(%HasFastDoubleElements(large_array));
 
 // Cause the array to grow beyond it's JSArray length. This will double the
 // size of the capacity and force the array into "slow" dictionary case.
 large_array[5] = Infinity;
@@ skipping 175 matching lines @@
   assertEquals(expected_array_value(2), large_array4[2]);
 }
 
 test_setter();
 test_setter();
 test_setter();
 %OptimizeFunctionOnNextCall(test_setter);
 test_setter();
 test_setter();
 test_setter();