Fix warnings in dart2js and analyzer caused by Fasta.

pkg/compiler/lib/src/parser/element_listener.dart

Index: pkg/compiler/lib/src/parser/element_listener.dart
diff --git a/pkg/compiler/lib/src/parser/element_listener.dart b/pkg/compiler/lib/src/parser/element_listener.dart
index b93b5e8723197d7c03e632ca8ad4b8ce6658a0bc..cb1894f8c889a4045c0e2c8545aa69aa1be06d30 100644
--- a/pkg/compiler/lib/src/parser/element_listener.dart
+++ b/pkg/compiler/lib/src/parser/element_listener.dart
@@ -751,14 +751,15 @@ class ElementListener extends Listener {
         break;
 
       case ErrorKind.AbstractNotSync:
-      case ErrorKind.SetterNotSync:
-      case ErrorKind.FactoryNotSync:
+      case ErrorKind.AwaitAsIdentifier:
       case ErrorKind.AwaitForNotAsync:
-      case ErrorKind.YieldNotGenerator:
-      case ErrorKind.YieldAsIdentifier:
-      case ErrorKind.GeneratorReturnsValue:
       case ErrorKind.AwaitNotAsync:
-      case ErrorKind.AwaitAsIdentifier:
+      case ErrorKind.FactoryNotSync:
+      case ErrorKind.GeneratorReturnsValue:
+      case ErrorKind.OnlyTry:
+      case ErrorKind.SetterNotSync:
+      case ErrorKind.YieldAsIdentifier:
+      case ErrorKind.YieldNotGenerator:
         return null; // Ignored. This error is already implemented elsewhere.
     }
     SourceSpan span = reporter.spanFromToken(token);