afford default cache policy, despite 6a29709906c6;

--- a/src/Pure/Thy/presentation.scala	Sun Aug 07 13:44:01 2022 +0200
+++ b/src/Pure/Thy/presentation.scala	Sun Aug 07 20:36:01 2022 +0200
@@ -134,8 +134,7 @@
           { case (session, thys) =>
               using(open_session(session)) { session_context =>
                 for (thy_name <- thys) yield {
-                  val theory_context =
-                    session_context.theory(thy_name, other_cache = Some(Term.Cache.none))
+                  val theory_context = session_context.theory(thy_name)
                   val theory = Export_Theory.read_theory(theory_context, permissive = true)
                   thy_name -> Node_Info.make(theory)
                 }