Re-insert linebreak in dwarf_stack_trace_test

tests/standalone/dwarf_stack_trace_test.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 /// VMOptions=--dwarf-stack-traces
 
 import 'package:unittest/unittest.dart';
 import 'dart:io';
 
 bar() {
   // Keep the 'throw' and its argument on separate lines.
-  throw "Hello, Dwarf!";
+  throw // force linebreak with dartfmt
+      "Hello, Dwarf!";
 }
 
 foo() {
   bar();
 }
 
 main() {
   String rawStack;
   try {
     foo();
@@ skipping 74 matching lines @@
         "bar",
         "dwarf_stack_trace_test.dart:12",
         "foo",
         "dwarf_stack_trace_test.dart:17",
         "main",
         "dwarf_stack_trace_test.dart:23",
         "main", // dispatcher
         "dwarf_stack_trace_test.dart:20"
       ]));
 }