protect some exception catching with not Debug.stack_trace

src/ide/gmain.ml

@@ -822,7 +822,7 @@ let sched =
     session_needs_saving := false;
     current_env_session := Some env;
     sched
-  with e ->
+  with e when not (Debug.test_flag Debug.stack_trace) ->
     eprintf "@[Error while opening session:@ %a@.@]"
       Exn_printer.exn_printer e;
     exit 1

src/session/session.ml

@@ -1556,7 +1556,8 @@ let read_xml_and_shapes xml_fn compressed_fn =
     let xml = Xml.from_file ~fixattrs:(fix_attributes ch) xml_fn in
     xml, !use_shapes
   with
-      e -> C.close_in ch; raise e
+      e when not (Debug.test_flag Debug.stack_trace) -> 
+        C.close_in ch; raise e
 end
 
 module ReadShapesNoCompress = ReadShapes(Compress.Compress_none)