Arbitrary self types v2: stabilize test changes

All the test changes necessary for stabilization here.

Author: adetaylor

compiler/rustc_codegen_cranelift/example/arbitrary_self_types_pointers_and_wrappers.rs

@@ -1,6 +1,6 @@
 // Adapted from rustc run-pass test suite
 
-#![feature(arbitrary_self_types, unsize, coerce_unsized, dispatch_from_dyn)]
+#![feature(unsize, coerce_unsized, dispatch_from_dyn)]
 
 use std::marker::Unsize;
 use std::ops::{CoerceUnsized, Deref, DispatchFromDyn};

compiler/rustc_codegen_cranelift/example/mini_core.rs

@@ -47,13 +47,6 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<*const U> for *const T {}
 impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<*mut U> for *mut T {}
 impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U>> for Box<T> {}
 
-#[lang = "legacy_receiver"]
-pub trait LegacyReceiver {}
-
-impl<T: ?Sized> LegacyReceiver for &T {}
-impl<T: ?Sized> LegacyReceiver for &mut T {}
-impl<T: ?Sized> LegacyReceiver for Box<T> {}
-
 #[lang = "copy"]
 pub trait Copy {}