This is part of the series started by D9375, and teaches isSafeToLoadUnconditionally to look through them.
I don't have a test case for this, but as a general utility, it makes sense.
Resigning as a reviewer to get a very stale review off my list of blocking tasks in phabricator. Please readd when desired.
This change should not be needed if the intrinsics are stripped by default.