tests: don't ignore compiler stderr in lib-defaults.rs

Author: jieyouxu

tests/ui/abi/lib-defaults.rs

@@ -1,6 +1,4 @@
 //@ run-pass
-//@ dont-check-compiler-stderr (rust-lang/rust#54222)
-
 //@ compile-flags: -lrust_test_helpers
 
 #[link(name = "rust_test_helpers", kind = "static")]