Make Error.prototype.toString spec compliant; and fix various side-effect-free error printing metho…

src/runtime/runtime-internal.cc

Index: src/runtime/runtime-internal.cc
diff --git a/src/runtime/runtime-internal.cc b/src/runtime/runtime-internal.cc
index 60f4307e30a97ccf7864b281d5de5d48312507b5..931525cbeb4e1f5ffba2f5064a8b598cc8d0a1d6 100644
--- a/src/runtime/runtime-internal.cc
+++ b/src/runtime/runtime-internal.cc
@@ -292,18 +292,6 @@ RUNTIME_FUNCTION(Runtime_MessageGetScript) {
 }
 
 
-RUNTIME_FUNCTION(Runtime_ErrorToStringRT) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 1);
-  CONVERT_ARG_HANDLE_CHECKED(JSObject, error, 0);
-  Handle<String> result;
-  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-      isolate, result,
-      isolate->error_tostring_helper()->Stringify(isolate, error));
-  return *result;
-}
-
-
 RUNTIME_FUNCTION(Runtime_FormatMessageString) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 4);