This makes the code more understandable from callsites, and also forces
users of this function to deal with the situation where the registrar
with a given client ID might not be present (it was previously silently
NPEing from some of the callsites).
This also adds a test helper method loadRegistrar(clientId) that retains
the old functionality for terseness in tests. It also fixes some instances
of using the load method with the wrong cachedness -- some uses in high-
traffic situations (WHOIS) that should have caching, but also low-traffic
reporting that don't benefit from caching so might as well always be
current.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=162990468