X64: Enable OSR as default on x64

Review URL: http://codereview.chromium.org/6480109

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6808 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/flag-definitions.h

@@ -134,11 +134,7 @@ DEFINE_bool(deoptimize_uncommon_cases, true, "deoptimize uncommon cases")
 DEFINE_bool(polymorphic_inlining, true, "polymorphic inlining")
 DEFINE_bool(aggressive_loop_invariant_motion, true,
             "aggressive motion of instructions out of loops")
-#ifdef V8_TARGET_ARCH_X64
-DEFINE_bool(use_osr, false, "use on-stack replacement")
-#else
 DEFINE_bool(use_osr, true, "use on-stack replacement")
-#endif
 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")