Add test case for replacing turbofan code for debugging.

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 63 matching lines @@
 
   # 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],
   'whitespaces': [PASS, NO_VARIANTS],
   'compiler/osr-assert': [PASS, NO_VARIANTS],
   'regress/regress-2185-2': [PASS, NO_VARIANTS],
 
+  # Issue 3660: Replacing activated TurboFan frames by unoptimized code does
+  # not work, but we expect it to not crash.
+  'debug-step-turbofan': [PASS, FAIL],
+
   # Support for %GetFrameDetails is missing and requires checkpoints.
   'debug-evaluate-bool-constructor': [PASS, NO_VARIANTS],
   'debug-evaluate-const': [PASS, NO_VARIANTS],
   'debug-evaluate-locals-optimized-double': [PASS, NO_VARIANTS],
   'debug-evaluate-locals-optimized': [PASS, NO_VARIANTS],
   'debug-evaluate-locals': [PASS, NO_VARIANTS],
   'debug-evaluate-with-context': [PASS, NO_VARIANTS],
   'debug-liveedit-double-call': [PASS, NO_VARIANTS],
   'debug-liveedit-restart-frame': [PASS, NO_VARIANTS],
   'debug-return-value': [PASS, NO_VARIANTS],
@@ skipping 460 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'
 ]