Deprecated attributes don't take 'feature' names and are paired with stable/unstable

Conflicts:
	src/libcore/atomic.rs
	src/libcore/finally.rs
	src/test/auxiliary/inherited_stability.rs
	src/test/auxiliary/lint_stability.rs

src/libstd/lib.rs

@@ -121,6 +121,7 @@
 #![feature(collections)]
 #![feature(rand)]
 #![feature(hash)]
+#![cfg_attr(test, feature(test))]
 
 // Don't link to std. We are std.
 #![no_std]