Split function block scoping into a separate flag

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 12a64d9eb7d3a809256402791b744ee57af1c630..6caa9b63a1d2226d7a622e8846ccc2e46c9b18f3 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -1836,6 +1836,7 @@ void Genesis::InitializeBuiltinTypedArrays() {
 
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_modules)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_array_includes)
+EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_block_function)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_regexps)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_arrow_functions)
 EMPTY_NATIVE_FUNCTIONS_FOR_FEATURE(harmony_tostring)
@@ -1873,6 +1874,7 @@ void Genesis::InstallNativeFunctions_harmony_proxies() {
 
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_modules)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_array_includes)
+EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_block_function)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_arrow_functions)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_proxies)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_sloppy)
@@ -2550,6 +2552,7 @@ bool Genesis::InstallNatives(ContextType context_type) {
 bool Genesis::InstallExperimentalNatives() {
   static const char* harmony_array_includes_natives[] = {
       "native harmony-array-includes.js", nullptr};
+  static const char* harmony_block_function_natives[] = {nullptr};
   static const char* harmony_proxies_natives[] = {"native proxy.js", nullptr};
   static const char* harmony_modules_natives[] = {nullptr};
   static const char* harmony_regexps_natives[] = {"native harmony-regexp.js",