Add infrastructure for skipping tests in GC stress mode.

test/mjsunit/array-constructor-feedback.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 17 matching lines @@
 // Flags: --allow-natives-syntax --smi-only-arrays --expose-gc
 // Flags: --noalways-opt
 
 // Test element kind of objects.
 // Since --smi-only-arrays affects builtins, its default setting at compile
 // time sticks if built with snapshot.  If --smi-only-arrays is deactivated
 // by default, only a no-snapshot build actually has smi-only arrays enabled
 // in this test case.  Depending on whether smi-only arrays are actually
 // enabled, this test takes the appropriate code path to check smi-only arrays.
 
-// Reset the GC stress mode to be off. Needed because AllocationMementos only
-// live for one gc, so a gc that happens in certain fragile areas of the test
-// can break assumptions.
-%SetFlags("--gc-interval=-1")
-
 // support_smi_only_arrays = %HasFastSmiElements(new Array(1,2,3,4,5,6,7,8));
 support_smi_only_arrays = true;
 
 if (support_smi_only_arrays) {
   print("Tests include smi-only arrays.");
 } else {
   print("Tests do NOT include smi-only arrays.");
 }
 
 var elements_kind = {
@@ skipping 195 matching lines @@
     // Try again
     %OptimizeFunctionOnNextCall(bar);
     a = bar(100);
     assertOptimized(bar);
     assertTrue(isHoley(a));
     a = bar(0);
     assertOptimized(bar);
     assertTrue(isHoley(a));
   })();
 }