Some assorted region hashing fixes.#43743

Merged

bors merged 2 commits intorust-lang:masterfrom michaelwoerister:gcx-tcx-switcheroo

Aug 11, 2017

+50-34

Commits on Aug 8, 2017

Implement HashStable for Xyz<'gcx> instead of Xyz<'lcx>.
michaelwoerister
committed

Commits on Aug 9, 2017

Erase/anonymize regions while computing TypeId hash.
michaelwoerister
committed