Remove the remaining feature gates

Author: Stjepan Glavina

Diff for: src/liballoc/benches/lib.rs

@@ -14,7 +14,6 @@
 #![feature(rand)]
 #![feature(repr_simd)]
 #![feature(slice_rotate)]
-#![feature(sort_unstable)]
 #![feature(test)]
 
 extern crate test;

Diff for: src/libcore/tests/lib.rs

@@ -34,7 +34,6 @@
 #![feature(slice_patterns)]
 #![feature(slice_rotate)]
 #![feature(sort_internals)]
-#![feature(sort_unstable)]
 #![feature(specialization)]
 #![feature(step_by)]
 #![feature(step_trait)]

Diff for: src/librustc/lib.rs

@@ -39,7 +39,6 @@
 #![feature(specialization)]
 #![feature(unboxed_closures)]
 #![feature(discriminant_value)]
-#![feature(sort_unstable)]
 #![feature(trace_macros)]
 #![feature(test)]
 

Diff for: src/librustc_incremental/lib.rs

@@ -20,7 +20,6 @@
 
 #![feature(rand)]
 #![feature(conservative_impl_trait)]
-#![feature(sort_unstable)]
 
 extern crate graphviz;
 #[macro_use] extern crate rustc;

Diff for: src/librustc_metadata/lib.rs

@@ -26,7 +26,6 @@
 #![feature(specialization)]
 #![feature(discriminant_value)]
 #![feature(rustc_private)]
-#![feature(sort_unstable)]
 
 #[macro_use]
 extern crate log;