Remove all harmony runtime flags which shipped in M51

src/messages.cc

Index: src/messages.cc
diff --git a/src/messages.cc b/src/messages.cc
index d5a15256b9fa0cfd75b5fda18aaa972dc15d47bf..2b0cdfc084d2ca1a666186b7caf71666df3ba05a 100644
--- a/src/messages.cc
+++ b/src/messages.cc
@@ -265,13 +265,11 @@ Handle<Object> CallSite::GetMethodName() {
     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)) {