Keep all type arguments in summaries - dynamic or not.

pkg/analyzer/lib/src/summary/format.dart

Index: pkg/analyzer/lib/src/summary/format.dart
diff --git a/pkg/analyzer/lib/src/summary/format.dart b/pkg/analyzer/lib/src/summary/format.dart
index 2b10d7d6733b27465b8e0decd8d439ec1e967bb5..7eab57f22f226e3683679af32052f1d28df342b7 100644
--- a/pkg/analyzer/lib/src/summary/format.dart
+++ b/pkg/analyzer/lib/src/summary/format.dart
@@ -548,8 +548,9 @@ class EntityRefBuilder extends Object with _EntityRefMixin implements idl.Entity
 
   /**
    * If this is an instantiation of a generic type or generic executable, the
-   * type arguments used to instantiate it.  Trailing type arguments of type
-   * `dynamic` are omitted.
+   * type arguments used to instantiate it.  If AST is used to create the
+   * summary, and the AST does not specify any type arguments, this list is
+   * empty.  If element model is used, this list is not empty.
    */
   void set typeArguments(List<EntityRefBuilder> _value) {
     assert(!_finished);