Delete query stats

These statistics are computable from the self-profile data and/or ad-hoc
collectable as needed, and in the meantime contribute to rustc bootstrap times.

compiler/rustc_interface/src/queries.rs

@@ -403,10 +403,6 @@ impl Compiler {
                 gcx.enter(rustc_query_impl::alloc_self_profile_query_strings);
             }
 
-            if self.session().opts.debugging_opts.query_stats {
-                gcx.enter(rustc_query_impl::print_stats);
-            }
-
             self.session()
                 .time("serialize_dep_graph", || gcx.enter(rustc_incremental::save_dep_graph));
         }