Remove all harmony runtime flags which shipped in M51

src/messages.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/messages.h"
 
 #include "src/api.h"
 #include "src/execution.h"
 #include "src/isolate-inl.h"
 #include "src/keys.h"
@@ skipping 247 matching lines @@
   if (!receiver->IsJSObject()) {
     return isolate_->factory()->null_value();
   }
 
   Handle<JSObject> obj = Handle<JSObject>::cast(receiver);
   Handle<Object> function_name(fun_->shared()->name(), isolate_);
   if (function_name->IsName()) {
     Handle<Name> name = Handle<Name>::cast(function_name);
     // ES2015 gives getters and setters name prefixes which must
     // be stripped to find the property name.
-    if (name->IsString() && FLAG_harmony_function_name) {
-      Handle<String> name_string = Handle<String>::cast(name);
-      if (name_string->IsUtf8EqualTo(CStrVector("get "), true) ||
-          name_string->IsUtf8EqualTo(CStrVector("set "), true)) {
-        name = isolate_->factory()->NewProperSubString(name_string, 4,
-                                                       name_string->length());
-      }
+    Handle<String> name_string = Handle<String>::cast(name);
+    if (name_string->IsUtf8EqualTo(CStrVector("get "), true) ||
+        name_string->IsUtf8EqualTo(CStrVector("set "), true)) {
+      name = isolate_->factory()->NewProperSubString(name_string, 4,
+                                                     name_string->length());
     }
     if (CheckMethodName(isolate_, obj, name, fun_,
                         LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR)) {
       return name;
     }
   }
 
   HandleScope outer_scope(isolate_);
   Handle<Object> result;
   for (PrototypeIterator iter(isolate_, obj, kStartAtReceiver); !iter.IsAtEnd();
@@ skipping 156 matching lines @@
       builder.AppendCharacter(*c);
     }
   }
 
   return builder.Finish();
 }
 
 
 }  // namespace internal
 }  // namespace v8