[field type tracking] Fix handling of cleared WeakCells

test/mjsunit/mjsunit.status

 # 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 136 matching lines @@
 
   # TODO(titzer): --always-opt incorrectly disables CrankShaft soft deopt points
   'result-table-min': [PASS, NO_VARIANTS],
   'result-table-max': [PASS, NO_VARIANTS],
   # TODO(titzer): too slow in --turbo mode due to O(n^2) graph verification.
   'regress/regress-1122': [PASS, NO_VARIANTS],
 
   # issue 4078:
   'allocation-site-info': [PASS, NO_VARIANTS],
 
-  # issue 4325:
-  'regress/regress-3960': [PASS, NO_VARIANTS],
-
   ##############################################################################
   # Too slow in debug mode with --stress-opt mode.
   'compiler/regress-stacktrace-methods': [PASS, ['mode == debug', SKIP]],
   'compiler/regress-funcaller': [PASS, ['mode == debug', SKIP]],
   'regress/regress-2318': [PASS, ['mode == debug', SKIP]],
   'regress/regress-create-exception': [PASS, ['mode == debug', SKIP]],
 
   ##############################################################################
   # Too slow in debug mode for validation of elements.
   'regress/regress-430201': [PASS, ['mode == debug', SKIP]],
@@ skipping 517 matching lines @@
   'd8-worker-sharedarraybuffer': [SKIP],
 }],  # 'predictable == True'
 
 ##############################################################################
 ['arch == ppc and simulator_run == True or arch == ppc64 and simulator_run == True', {
 
   # take too long with the simulator.
   'regress/regress-1132': [SKIP],
 }],  # 'arch == ppc and simulator_run == True'
 ]