Remove unused --peephole-optimization flag.

src/flag-definitions.h

 // 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 150 matching lines @@
 
 DEFINE_bool(trace_osr, false, "trace on-stack replacement")
 DEFINE_int(stress_runs, 0, "number of stress runs")
 DEFINE_bool(optimize_closures, true, "optimize closures")
 DEFINE_int(loop_weight, 1, "loop weight for representation inference")
 
 // assembler-ia32.cc / assembler-arm.cc / assembler-x64.cc
 DEFINE_bool(debug_code, false,
             "generate extra code (assertions) for debugging")
 DEFINE_bool(code_comments, false, "emit comments in code disassembly")
-DEFINE_bool(peephole_optimization, true,
-            "perform peephole optimizations in assembly code")
 DEFINE_bool(enable_sse2, true,
             "enable use of SSE2 instructions if available")
 DEFINE_bool(enable_sse3, true,
             "enable use of SSE3 instructions if available")
 DEFINE_bool(enable_sse4_1, true,
             "enable use of SSE4.1 instructions if available")
 DEFINE_bool(enable_cmov, true,
             "enable use of CMOV instruction if available")
 DEFINE_bool(enable_rdtsc, true,
             "enable use of RDTSC instruction if available")
@@ skipping 396 matching lines @@
 #undef DEFINE_bool
 #undef DEFINE_int
 #undef DEFINE_string
 #undef DEFINE_implication
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS