Remove --harmony-exponentiation-operator flag

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 6fd5917f1a95a48a9cb7ce5c3c6cdd8704006615..7090c5aeaa2a5d466296010bf511814175b49774 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -2729,7 +2729,6 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(intl_extra)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_explicit_tailcalls)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_tailcalls)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_restrictive_declarations)
-EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_exponentiation_operator)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_string_padding)
 #ifdef V8_I18N_SUPPORT
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(icu_case_mapping)
@@ -3318,7 +3317,6 @@ bool Genesis::InstallExperimentalNatives() {
   static const char* harmony_object_own_property_descriptors_natives[] = {
       nullptr};
   static const char* harmony_array_prototype_values_natives[] = {nullptr};
-  static const char* harmony_exponentiation_operator_natives[] = {nullptr};
   static const char* harmony_string_padding_natives[] = {
       "native harmony-string-padding.js", nullptr};
 #ifdef V8_I18N_SUPPORT