Track async state in parser.

pkg/analyzer/lib/src/summary/fasta/summary_builder.dart

Index: pkg/analyzer/lib/src/summary/fasta/summary_builder.dart
diff --git a/pkg/analyzer/lib/src/summary/fasta/summary_builder.dart b/pkg/analyzer/lib/src/summary/fasta/summary_builder.dart
index 499ebaeb5562fe86205530dc4673094ddeeef5ed..0d360fa5ba54f2fbeb6905d25b284b2707facd0b 100644
--- a/pkg/analyzer/lib/src/summary/fasta/summary_builder.dart
+++ b/pkg/analyzer/lib/src/summary/fasta/summary_builder.dart
@@ -98,7 +98,7 @@ class ConstExpressionBuilder extends ExpressionListener {
   final Uri uri;
   Parser parser;
   ConstExpressionBuilder(this.uri) {
-    parser = new Parser(this, asyncAwaitKeywordsEnabled: true);
+    parser = new Parser(this);
   }
   bool get forConst => true;
 
@@ -610,7 +610,7 @@ class InitializerBuilder extends ExpressionListener {
   int _inArguments = 0;
 
   InitializerBuilder(this.uri) {
-    parser = new Parser(this, asyncAwaitKeywordsEnabled: true);
+    parser = new Parser(this);
   }
 
   bool get ignore => super.ignore || _inArguments > 0;