Disable lowering to StringAdd due to various issues.

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 56 matching lines @@
   'debug-references': [PASS, NO_VARIANTS],
   'regress/regress-263': [PASS, NO_VARIANTS],
 
   # TODO(rossberg): Typer doesn't like contexts very much.
   'harmony/block-conflicts': [PASS, NO_VARIANTS],
   'harmony/block-for': [PASS, NO_VARIANTS],
   'harmony/block-leave': [PASS, NO_VARIANTS],
   'harmony/block-let-crankshaft': [PASS, NO_VARIANTS],
   'harmony/empty-for': [PASS, NO_VARIANTS],
 
-  # TODO(mstarzinger): Typed lowering screws up valueOf vs. toString order.
-  'regress/regress-760-1': [PASS, NO_VARIANTS],
-  'regress/regress-760-2': [PASS, NO_VARIANTS],
-  'harmony/proxies-json': [PASS, NO_VARIANTS],
-
-  # Unused code is optimized away, think about fixing the test case.
-  'string-oom-concat': [PASS, NO_VARIANTS],
-  'regress/regress-crbug-357052': [PASS, NO_VARIANTS],
-
   # Some tests are over-restrictive about object layout.
   'array-constructor-feedback': [PASS, NO_VARIANTS],
   'array-feedback': [PASS, NO_VARIANTS],
   'elements-kind': [PASS, NO_VARIANTS],
 
   # Some tests are just too slow to run for now.
   'bit-not': [PASS, NO_VARIANTS],
   'json2': [PASS, NO_VARIANTS],
   'packed-elements': [PASS, NO_VARIANTS],
   'unbox-double-arrays': [PASS, NO_VARIANTS],
@@ skipping 457 matching lines @@
   'never-optimize': [SKIP],
   'regress/regress-2185-2': [SKIP],
   'harmony/object-observe': [SKIP],
   'readonly': [SKIP],
   'array-feedback': [SKIP],
 
   # Deopt every n garbage collections collides with deopt every n times.
   'regress/regress-2653': [SKIP],
 }],  # 'deopt_fuzzer == True'
 ]