Improve and simplify removal of unreachable code

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
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 322 matching lines @@
         '../../src/hydrogen-bch.cc',
         '../../src/hydrogen-bch.h',
         '../../src/hydrogen-canonicalize.cc',
         '../../src/hydrogen-canonicalize.h',
         '../../src/hydrogen-check-elimination.cc',
         '../../src/hydrogen-check-elimination.h',
         '../../src/hydrogen-dce.cc',
         '../../src/hydrogen-dce.h',
         '../../src/hydrogen-dehoist.cc',
         '../../src/hydrogen-dehoist.h',
-        '../../src/hydrogen-deoptimizing-mark.cc',
-        '../../src/hydrogen-deoptimizing-mark.h',
         '../../src/hydrogen-environment-liveness.cc',
         '../../src/hydrogen-environment-liveness.h',
         '../../src/hydrogen-escape-analysis.cc',
         '../../src/hydrogen-escape-analysis.h',
         '../../src/hydrogen-instructions.cc',
         '../../src/hydrogen-instructions.h',
         '../../src/hydrogen.cc',
         '../../src/hydrogen.h',
         '../../src/hydrogen-gvn.cc',
         '../../src/hydrogen-gvn.h',
         '../../src/hydrogen-infer-representation.cc',
         '../../src/hydrogen-infer-representation.h',
         '../../src/hydrogen-infer-types.cc',
         '../../src/hydrogen-infer-types.h',
         '../../src/hydrogen-load-elimination.cc',
         '../../src/hydrogen-load-elimination.h',
         '../../src/hydrogen-mark-deoptimize.cc',
         '../../src/hydrogen-mark-deoptimize.h',
+        '../../src/hydrogen-mark-unreachable.cc',
+        '../../src/hydrogen-mark-unreachable.h',
         '../../src/hydrogen-minus-zero.cc',
         '../../src/hydrogen-minus-zero.h',
         '../../src/hydrogen-osr.cc',
         '../../src/hydrogen-osr.h',
         '../../src/hydrogen-range-analysis.cc',
         '../../src/hydrogen-range-analysis.h',
         '../../src/hydrogen-redundant-phi.cc',
         '../../src/hydrogen-redundant-phi.h',
         '../../src/hydrogen-removable-simulates.cc',
         '../../src/hydrogen-removable-simulates.h',
@@ skipping 22 matching lines @@
         '../../src/json-stringifier.h',
         '../../src/jsregexp-inl.h',
         '../../src/jsregexp.cc',
         '../../src/jsregexp.h',
         '../../src/lazy-instance.h',
         '../../src/list-inl.h',
         '../../src/list.h',
         '../../src/lithium-allocator-inl.h',
         '../../src/lithium-allocator.cc',
         '../../src/lithium-allocator.h',
+        '../../src/lithium-codegen.cc',
+        '../../src/lithium-codegen.h',
         '../../src/lithium.cc',
         '../../src/lithium.h',
         '../../src/liveedit.cc',
         '../../src/liveedit.h',
         '../../src/log-inl.h',
         '../../src/log-utils.cc',
         '../../src/log-utils.h',
         '../../src/log.cc',
         '../../src/log.h',
         '../../src/macro-assembler.h',
@@ skipping 630 matching lines @@
         }],
         ['v8_compress_startup_data=="bz2"', {
           'libraries': [
             '-lbz2',
           ]
         }],
       ],
     },
   ],
 }