Remove unused feature gates

Author: oli-obk

src/test/ui/existential_types/auxiliary/cross_crate_ice.rs

@@ -1,6 +1,5 @@
 // Crate that exports an existential type. Used for testing cross-crate.
 
-#![feature(const_fn)]
 #![crate_type="rlib"]
 
 #![feature(existential_type)]

src/test/ui/existential_types/auxiliary/cross_crate_ice2.rs

@@ -1,6 +1,5 @@
 // Crate that exports an existential type. Used for testing cross-crate.
 
-#![feature(const_fn)]
 #![crate_type="rlib"]
 
 #![feature(existential_type)]