Remove deprecated parts of dart:async.

sdk/lib/_internal/compiler/implementation/dart2js.dart

Index: sdk/lib/_internal/compiler/implementation/dart2js.dart
diff --git a/sdk/lib/_internal/compiler/implementation/dart2js.dart b/sdk/lib/_internal/compiler/implementation/dart2js.dart
index a827bf6ea03e02ee597e117055cf8118d5adc0b5..78825c5c1ad7820afcfaa3a8b603763e0c5cf556 100644
--- a/sdk/lib/_internal/compiler/implementation/dart2js.dart
+++ b/sdk/lib/_internal/compiler/implementation/dart2js.dart
@@ -590,7 +590,7 @@ void helpAndFail(String message) {
 }
 
 void main(List<String> arguments) {
-  runZoned(() => compilerMain(arguments), onError: (exception) {
+  runZoned(() => compilerMain(arguments), onError: (exception, trace) {
     try {
       print('Internal error: $exception');
     } catch (ignored) {
@@ -598,7 +598,6 @@ void main(List<String> arguments) {
     }
 
     try {
-      var trace = getAttachedStackTrace(exception);
       if (trace != null) {
         print(trace);
       }