Bring #import back for Core compatibility (#7177)

The primitive for dynamic import has been renamed to `%import`,
but there are a few libraries directly rely on compiler primitives.

Author: cometkim

compiler/ml/translcore.ml

@@ -396,6 +396,7 @@ let primitives_table =
       ("#nullable_to_opt", Pnull_to_opt);
       ("#undefined_to_opt", Pundefined_to_opt);
       ("#makemutablelist", Pmakelist Mutable);
+      ("#import", Pimport);
       (* FIXME: Deprecated *)
       ("%obj_field", Parrayrefu);
     |]