Reland "Track the 'awaiter return' call stack..."

pkg/kernel/lib/transformations/async.dart

Index: pkg/kernel/lib/transformations/async.dart
diff --git a/pkg/kernel/lib/transformations/async.dart b/pkg/kernel/lib/transformations/async.dart
index b01f71a896f001a9bff950ed9929d9dbde6be1d9..352b4168c4c7828a42483e7b5e3ab400acac802c 100644
--- a/pkg/kernel/lib/transformations/async.dart
+++ b/pkg/kernel/lib/transformations/async.dart
@@ -417,7 +417,8 @@ class ExpressionLifter extends Transformer {
     Arguments arguments = new Arguments(<Expression>[
       expr.operand,
       new VariableGet(R.thenContinuationVariable),
-      new VariableGet(R.catchErrorContinuationVariable)
+      new VariableGet(R.catchErrorContinuationVariable),
+      new VariableGet(R.nestedClosureVariable),
     ]);
     statements.add(new ExpressionStatement(
         new StaticInvocation(R.helper.awaitHelper, arguments)