Use run-pass test

Author: tiif

tests/ui/internal/unstable_impl_codegen.rs

@@ -1,5 +1,5 @@
 //@ aux-build:unstable_impl_codegen_aux2.rs
-//@ check-pass
+//@ run-pass
 
 /// Downstream crate for unstable impl codegen test
 /// that depends on upstream crate in