Revert "Register snapshots"

This reverts commit d6d12d90ff.

src/libcore/iter-trait.rs

@@ -17,6 +17,10 @@
 
 use cmp::{Eq, Ord};
 
+#[cfg(stage0)]
+use inst::{IMPL_T, EACH, SIZE_HINT};
+#[cfg(stage1)]
+#[cfg(stage2)]
 use self::inst::{IMPL_T, EACH, SIZE_HINT};
 
 impl<A> IMPL_T<A>: iter::BaseIter<A> {