This way we need the common types only once per process and we don't
need to recreate them for every compilation. It uses the same pattern
that we already apply to caching operators. This simplifies the type
cache a lot.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/1209513002

Cr-Commit-Position: refs/heads/master@{#29251}