x.py: remove fixme by deleting code

As far as I can tell, this parameter was never used, so just delete it
as unnecessary.

src/bootstrap/tool.rs

@@ -286,7 +286,6 @@ macro_rules! bootstrap_tool {
         $name:ident, $path:expr, $tool_name:expr
         $(,is_external_tool = $external:expr)*
         $(,is_unstable_tool = $unstable:expr)*
-        $(,features = $features:expr)*
         ;
     )+) => {
         #[derive(Copy, PartialEq, Eq, Clone)]
@@ -349,12 +348,7 @@ macro_rules! bootstrap_tool {
                     } else {
                         SourceType::InTree
                     },
-                    extra_features: {
-                        // FIXME(#60643): avoid this lint by using `_`
-                        let mut _tmp = Vec::new();
-                        $(_tmp.extend($features);)*
-                        _tmp
-                    },
+                    extra_features: vec![],
                 }).expect("expected to build -- essential tool")
             }
         }