chore: checkpoint before Python removal

vendor/pin-project/tests/ui/cfg/cfg_attr-resolve.rs

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use std::pin::Pin;
+
+#[cfg_attr(any(), pin_project::pin_project)]
+struct Foo<T> {
+    f: T,
+}
+
+fn main() {
+    let mut x = Foo { f: 0_u8 };
+    let _ = Pin::new(&mut x).project(); //~ ERROR E0599
+}