Remove unused flag --print-cfg.

src/flag-definitions.h

 // Copyright 2008 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 252 matching lines @@
             "pretty print source code for builtins")
 DEFINE_bool(print_ast, false, "print source AST")
 DEFINE_bool(print_builtin_ast, false, "print source AST for builtins")
 DEFINE_bool(trace_calls, false, "trace calls")
 DEFINE_bool(trace_builtin_calls, false, "trace builtins calls")
 DEFINE_string(stop_at, "", "function name where to insert a breakpoint")
 
 // compiler.cc
 DEFINE_bool(print_builtin_scopes, false, "print scopes for builtins")
 DEFINE_bool(print_scopes, false, "print scopes")
-DEFINE_bool(print_cfg, false, "print control-flow graph")
 
 // contexts.cc
 DEFINE_bool(trace_contexts, false, "trace contexts operations")
 
 // heap.cc
 DEFINE_bool(gc_greedy, false, "perform GC prior to some allocations")
 DEFINE_bool(gc_verbose, false, "print stuff during garbage collection")
 DEFINE_bool(heap_stats, false, "report heap statistics before and after GC")
 DEFINE_bool(code_stats, false, "report code statistics after GC")
 DEFINE_bool(verify_heap, false, "verify heap pointers before and after GC")
@@ skipping 101 matching lines @@
 #undef FLAG
 
 #undef DEFINE_bool
 #undef DEFINE_int
 #undef DEFINE_string
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META