Make caches misses throw by default intead of inline-generating

Summary:
Ref T4103. Ref T10078. Currently, when a user misses a cache we just build it for them.

This is the behavior we want for the the viewer (so we don't have to build every cache up front if we don't actually need them), but not the right behavior for other users (since it allows performance problems to go undetected).

Make inline cache generation strict by default, then make sure all the things that rely on cache data request the correct data (well, all of the things identified by unit tests, at least: there might be some more stuff I haven't hit yet).

This fixes test failures in D16040, and backports a piece of that change.

Test Plan: Identified and then fixed failures with arc unit --everything.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4103, T10078

Differential Revision: https://secure.phabricator.com/D16042