Fix bootstrap build_all test

Author: GuillaumeGomez

src/bootstrap/src/core/builder/tests.rs

@@ -647,7 +647,7 @@ mod dist {
         let mut builder = Builder::new(&build);
         builder.run_step_descriptions(
             &Builder::get_step_descriptions(Kind::Build),
-            &["compiler/rustc".into(), "library".into()],
+            &["compiler/rustc".into(), "std".into()],
         );
 
         assert_eq!(