Handle switch continue

tests/compiler/dart2js/kernel/compile_from_dill_test_helper.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.
 
 // Helper to test compilation equivalence between source and .dill based
 // compilation.
 library dart2js.kernel.compile_from_dill_test_helper;
 
 import 'dart:async';
 
@@ skipping 168 matching lines @@
       if (a == b) break outer3;
       if (a != b) continue outer3;
     }
   }
   print(x);
 }
 '''
   }, expectIdenticalOutput: false),
   const Test(const {
     'main.dart': '''
+main() {
+  var x = 42;
+  int i = 0;
+  switch (i) {
+  case 0:
+     print(x);
+     continue label1;
+  label1:
+     case 1:
+     print(x);
+     break;
+  }
+}    
+'''
+  }, expectIdenticalOutput: false),
+  const Test(const {
+    'main.dart': '''
 class A<U,V> {
   var a = U;
   var b = V;
 }
 class B<Q, R> extends A<R, W<Q>> {
 }
 class C<Y> extends B<Y, W<Y>> {
 }
 class W<Z> {}
 main() {
@@ skipping 223 matching lines @@
       Map<String, BufferedOutputSink> map2 = collector2.outputMap[outputType];
       checkSets(map1.keys, map2.keys, 'output', equality);
       map1.forEach((String name, BufferedOutputSink output1) {
         BufferedOutputSink output2 = map2[name];
         Expect.stringEquals(output1.text, output2.text);
       });
     });
   }
   return ResultKind.success;
 }