std: remove gc module.

Author: eddyb

src/libstd/gc.rs

@@ -137,7 +137,6 @@ extern crate rustrt;
 #[cfg(test)] pub use realstd::cmp;
 #[cfg(test)] pub use realstd::ty;
 #[cfg(test)] pub use realstd::boxed;
-#[cfg(test)] pub use realstd::gc;
 
 
 // NB: These reexports are in the order they should be listed in rustdoc
@@ -220,9 +219,6 @@ pub mod rand;
 
 pub mod ascii;
 
-#[cfg(not(test))]
-pub mod gc;
-
 pub mod time;
 
 /* Common traits */