disable write_updates from f425bbc4b2eb for now: "isabelle build_process -rf" does not quite work yet;

--- a/src/Pure/Build/build_process.scala	Sat Mar 09 22:02:27 2024 +0100
+++ b/src/Pure/Build/build_process.scala	Sat Mar 09 22:04:07 2024 +0100
@@ -886,7 +886,7 @@
 
       if (updates.exists(_.defined)) {
         val serial = state.next_serial
-        write_updates(db, serial, updates)
+        // FIXME write_updates(db, serial, updates)
         stamp_worker(db, worker_uuid, serial)
         state.copy(serial = serial)
       }