[es6] Fix scoping for default parameters in arrow functions

tools/gyp/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
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@@ skipping 845 matching lines @@
         '../../src/msan.h',
         '../../src/objects-debug.cc',
         '../../src/objects-inl.h',
         '../../src/objects-printer.cc',
         '../../src/objects.cc',
         '../../src/objects.h',
         '../../src/optimizing-compile-dispatcher.cc',
         '../../src/optimizing-compile-dispatcher.h',
         '../../src/ostreams.cc',
         '../../src/ostreams.h',
-        '../../src/pattern-rewriter.cc',
+        '../../src/parameter-initializer-rewriter.cc',
+        '../../src/parameter-initializer-rewriter.h',
         '../../src/parser.cc',
         '../../src/parser.h',
+        '../../src/pattern-rewriter.cc',
         '../../src/pending-compilation-error-handler.cc',
         '../../src/pending-compilation-error-handler.h',
         '../../src/preparse-data-format.h',
         '../../src/preparse-data.cc',
         '../../src/preparse-data.h',
         '../../src/preparser.cc',
         '../../src/preparser.h',
         '../../src/prettyprinter.cc',
         '../../src/prettyprinter.h',
         '../../src/profiler/allocation-tracker.cc',
@@ skipping 1215 matching lines @@
         }],
         ['want_separate_host_toolset==1', {
           'toolsets': ['host'],
         }, {
           'toolsets': ['target'],
         }],
       ],
     },
   ],
 }