Rollup merge of #21925 - sfackler:allow-missing-copy, r=alexcrichton

This was particularly helpful in the time just after OIBIT's
implementation to make sure things that were supposed to be Copy
continued to be, but it's now creates a lot of noise for types that
intentionally don't want to be Copy.

r? @alexcrichton

src/test/compile-fail/lint-dead-code-1.rs

@@ -12,7 +12,6 @@
 #![allow(unused_variables)]
 #![allow(non_camel_case_types)]
 #![allow(non_upper_case_globals)]
-#![allow(missing_copy_implementations)]
 #![deny(dead_code)]
 #![feature(core)]
 

src/test/compile-fail/lint-missing-doc.rs

@@ -12,7 +12,6 @@
 // injected intrinsics by the compiler.
 #![deny(missing_docs)]
 #![allow(dead_code)]
-#![allow(missing_copy_implementations)]
 
 //! Some garbage docs for the crate here
 #![doc="More garbage"]

src/test/compile-fail/missing_debug_impls.rs

@@ -10,7 +10,7 @@
 
 // compile-flags: --crate-type lib
 #![deny(missing_debug_implementations)]
-#![allow(unused, missing_copy_implementations)]
+#![allow(unused)]
 
 use std::fmt;