Auto merge of #34031 - jseyfried:fix_cfg_bug, r=eddyb

Fix a regression in the configuration folder

This fixes #34028, a regression caused by #33706 in which unconfigured impl items generated by a macro in an impl item position are not removed.
r? @nrc

src/test/compile-fail/issue-34028.rs

@@ -0,0 +1,21 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(rustc_attrs)]
+
+macro_rules! m {
+    () => { #[cfg(any())] fn f() {} }
+}
+
+trait T {}
+impl T for () { m!(); }
+
+#[rustc_error]
+fn main() {} //~ ERROR compilation successful