Run dartfmt on all files under runtime.

runtime/tests/vm/dart/spawn_shutdown_test.dart

Index: runtime/tests/vm/dart/spawn_shutdown_test.dart
diff --git a/runtime/tests/vm/dart/spawn_shutdown_test.dart b/runtime/tests/vm/dart/spawn_shutdown_test.dart
index 13fb2b8e211630c7e2c120d0131e60e2dc466e8c..235a0d86153d965534b180855d042dee08d3eab8 100644
--- a/runtime/tests/vm/dart/spawn_shutdown_test.dart
+++ b/runtime/tests/vm/dart/spawn_shutdown_test.dart
@@ -27,7 +27,9 @@ void worker(SendPort parentPort) {
   var port = new RawReceivePort();
 
   // This worker will exit when it receives any message.
-  port.handler = (_) { port.close(); };
+  port.handler = (_) {
+    port.close();
+  };
 
   // Send a message to terminate our parent isolate.
   if (parentPort != null) {
@@ -40,7 +42,7 @@ void worker(SendPort parentPort) {
 
 void main() {
   const numWorkers = 50;
-  const delay = const Duration(milliseconds:(1000 ~/ numWorkers));
+  const delay = const Duration(milliseconds: (1000 ~/ numWorkers));
   const exitDelay = const Duration(seconds: 2);
 
   // Take about a second to spin up our workers in a staggered