Run dartfmt on kernel package

pkg/kernel/testcases/closures/closure_in_initializer_closure.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.md file.
 
 class C {
   var t;
-  C.foo(f) : t = (() {
-      var prefix;
-      var g = (x) {
-        f("$prefix$x");
-      };
-      prefix = 'hest';
-      return g;
-    }) {
+  C.foo(f)
+      : t = (() {
+          var prefix;
+          var g = (x) {
+            f("$prefix$x");
+          };
+          prefix = 'hest';
+          return g;
+        }) {
     print(1);
   }
 }
 
 main() {
   print(0);
   var c = new C.foo((x) => print(x));
   print(2);
   c.t()('fisk');
   print(3);
 }