This merges the mrucache and numerics into one folder, to prevent
having to make two identical versions of logging.

BUG=angleproject:2044

Change-Id: Iba6dab05b21eb9ba0de44f27a90579c590a9a7fd
Reviewed-on: https://chromium-review.googlesource.com/522870Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>