auto merge of #10182 : alexcrichton/rust/typeid-intrinsic, r=nikomatsakis

This isn't quite as fancy as the struct in #9913, but I'm not sure we should be exposing crate names/hashes of the types. That being said, it'd be pretty easy to extend this (the deterministic hashing regardless of what crate you're in was the hard part).

diff --cc src/librustc/middle/trans/intrinsic.rs
Simple merge

diff --cc src/librustc/middle/ty.rs
Simple merge

diff --cc src/librustc/middle/typeck/check/mod.rs
Simple merge

diff --cc src/libstd/unstable/intrinsics.rs
Simple merge