Support while loop in analyzer2dart.

pkg/analyzer2dart/test/end2end_test.dart

Index: pkg/analyzer2dart/test/end2end_test.dart
diff --git a/pkg/analyzer2dart/test/end2end_test.dart b/pkg/analyzer2dart/test/end2end_test.dart
index 3cfde576c7075f0a0724c50cd7182dd49d3642d6..6cc500c065eb48a2ca1c50a36084a848354b4308 100644
--- a/pkg/analyzer2dart/test/end2end_test.dart
+++ b/pkg/analyzer2dart/test/end2end_test.dart
@@ -27,7 +27,7 @@ main() {
 
 checkResult(TestSpec result) {
   String input = result.input;
-  String expectedOutput = result.output;
+  String expectedOutput = result.output.trim();
 
   CollectingOutputProvider outputProvider = new CollectingOutputProvider();
   MemoryResourceProvider provider = new MemoryResourceProvider();
@@ -40,6 +40,6 @@ checkResult(TestSpec result) {
   ClosedWorld world = driver.computeWorld(entryPoint);
   ConvertedWorld convertedWorld = convertWorld(world);
   compileToDart(driver, convertedWorld);
-  String output = outputProvider.output.text;
+  String output = outputProvider.output.text.trim();
   expect(output, equals(expectedOutput));
 }