remove QueryTermRef from Allocator

src/prolog/debray_allocator.rs

@@ -348,8 +348,8 @@ impl<'a> Allocator<'a> for DebrayAllocator<'a>
         self.bindings
     }
     
-    fn advance(&mut self, _: GenContext, term: QueryTermRef<'a>) {
+    fn advance(&mut self, _: GenContext, arity: usize) {
         self.arg_c   = 1;
-        self.temp_lb = term.arity() + 1;
+        self.temp_lb = arity + 1;
     }
 }