[Interpreter] Add a simple dead-code elimination bytecode optimizer.

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 880 matching lines @@
         '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',
         'interpreter/bytecode-array-writer.cc',
         'interpreter/bytecode-array-writer.h',
+        'interpreter/bytecode-dead-code-optimizer.cc',
+        'interpreter/bytecode-dead-code-optimizer.h',
         'interpreter/bytecode-label.h',
+        'interpreter/bytecode-generator.cc',
+        'interpreter/bytecode-generator.h',
         'interpreter/bytecode-peephole-optimizer.cc',
         'interpreter/bytecode-peephole-optimizer.h',
         'interpreter/bytecode-pipeline.cc',
         'interpreter/bytecode-pipeline.h',
         'interpreter/bytecode-register-allocator.cc',
         'interpreter/bytecode-register-allocator.h',
         'interpreter/bytecode-register-optimizer.cc',
         'interpreter/bytecode-register-optimizer.h',
-        'interpreter/bytecode-generator.cc',
-        'interpreter/bytecode-generator.h',
         'interpreter/bytecode-traits.h',
         'interpreter/constant-array-builder.cc',
         'interpreter/constant-array-builder.h',
         'interpreter/control-flow-builders.cc',
         'interpreter/control-flow-builders.h',
         'interpreter/handler-table-builder.cc',
         'interpreter/handler-table-builder.h',
         'interpreter/interpreter.cc',
         'interpreter/interpreter.h',
         'interpreter/interpreter-assembler.cc',
@@ skipping 1359 matching lines @@
         }],
         ['want_separate_host_toolset==1', {
           'toolsets': ['host'],
         }, {
           'toolsets': ['target'],
         }],
       ],
     },
   ],
 }