Support unreachable code in blocks in analyzer2dart.

pkg/analyzer2dart/lib/src/cps_generator.dart

 // Copyright (c) 2014, 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.
 
 library analyzer2dart.cps_generator;
 
 import 'package:analyzer/analyzer.dart';
 
 import 'package:compiler/implementation/elements/elements.dart' as dart2js;
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 212 matching lines @@
         subbuild(node.elseExpression));
   }
 
   @override
   visitIfStatement(IfStatement node) {
     irBuilder.buildIf(
         build(node.condition),
         subbuild(node.thenStatement),
         subbuild(node.elseStatement));
   }
+
+  @override
+  visitBlock(Block node) {
+    irBuilder.buildBlock(node.statements, build);
+  }
 }