[stubs] Port KeyedStoreIC_Megamorphic stub to Turbofan

src/v8.gyp

 # 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 942 matching lines @@
         'ic/handler-compiler.h',
         'ic/handler-configuration-inl.h',
         'ic/handler-configuration.h',
         'ic/ic-inl.h',
         'ic/ic-state.cc',
         'ic/ic-state.h',
         'ic/ic.cc',
         'ic/ic.h',
         'ic/ic-compiler.cc',
         'ic/ic-compiler.h',
+        'ic/keyed-store-generic.cc',
+        'ic/keyed-store-generic.h',
         'identity-map.cc',
         'identity-map.h',
         'interface-descriptors.cc',
         'interface-descriptors.h',
         'interpreter/bytecodes.cc',
         'interpreter/bytecodes.h',
         'interpreter/bytecode-array-builder.cc',
         'interpreter/bytecode-array-builder.h',
         'interpreter/bytecode-array-iterator.cc',
         'interpreter/bytecode-array-iterator.h',
@@ skipping 1496 matching lines @@
       'conditions': [
         ['want_separate_host_toolset_mkpeephole==1', {
           'toolsets': ['host'],
         }, {
           'toolsets': ['target'],
         }],
       ],
     },
   ],
 }