librustc: Remove trans::reflect and the opaque and ty_visitor lang items.

Author: luqmana

reference.md

@@ -2279,8 +2279,6 @@ These types help drive the compiler's analysis
   : The lifetime parameter should be considered invariant
 * `malloc`
   : Allocate memory on the managed heap.
-* `opaque`
-  : ___Needs filling in___
 * `owned_box`
   : ___Needs filling in___
 * `stack_exhausted`
@@ -2295,8 +2293,6 @@ These types help drive the compiler's analysis
   : The type parameter should be considered invariant
 * `ty_desc`
   : ___Needs filling in___
-* `ty_visitor`
-  : ___Needs filling in___
 
 > **Note:** This list is likely to become out of date. We should auto-generate
 > it from `librustc/middle/lang_items.rs`.