Assert that we do not infinitely loop in ir::Item::name_target
Assert that we do not infinitely loop in ir::Item::name_target

This re-uses the infrastructure used when asserting that
`ItemAncestorsIter` does not infinitely loop in `ir::Item::name_target`.

rust-lang/rust-bindgen,emilio/rust-bindgen,rust-lang/rust-bindgen,emilio/rust-bindgen,emilio/rust-bindgen,emilio/rust-bindgen,rust-lang/rust-bindgen,rust-lang/rust-bindgen,emilio/rust-bindgen