Test mjsunit/allocation-site-info is flaky without explicit gc()

test/mjsunit/allocation-site-info.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 396 matching lines @@
    obj[0][0] = 3.5;
    obj[1][0][0] = "goodbye";
    assertKind(elements_kind.fast_double, obj[0]);
    assertKind(elements_kind.fast, obj[1][0]);
 
    obj = get_deep_nested_literal();
    assertKind(elements_kind.fast_double, obj[0]);
    assertKind(elements_kind.fast, obj[1][0]);
   })();
 
+  // Perform a gc because without it the test below can experience an
+  // allocation failure at an inconvenient point. Allocation mementos get
+  // cleared on gc, and they can't deliver elements kind feedback when that
+  // happens.
+  gc();
 
   // Make sure object literals with array fields benefit from the type feedback
   // that allocation mementos provide.
   (function() {
     // A literal in an object
     function get_object_literal() {
       var literal = {
         array: [1,2,3],
         data: 3.5
       };
@@ skipping 54 matching lines @@
     obj[0][0] = 3.5;
     obj[1][0][0] = "goodbye";
     assertKind(elements_kind.fast_double, obj[0]);
     assertKind(elements_kind.fast, obj[1][0]);
 
     obj = get_deep_nested_literal();
     assertKind(elements_kind.fast_double, obj[0]);
     assertKind(elements_kind.fast, obj[1][0]);
   })();
 }