This new OSSA invariant simplifies many optimizations because they don't have to take care of the corner case of incomplete lifetimes in dead-end blocks.
The implementation basically consists of these changes:
* add the lifetime completion utility
* add a flag in SILFunction which tells optimization that they need to run the lifetime completion utility
* let all optimizations complete lifetimes if necessary
* enable the ownership verifier to check complete lifetimes
Now that it can be called on partial_apply instructions,
insertAfterFullEvaluation does not name what the function does. One
could imagine a function which inserted after the applies of
(non-escaping) partial_applies.
... and use that API in FullApplySite::insertAfterInvocation.
Also change FullApplySite::insertAfterInvocation/insertAfterFullEvaluation to directly pass a SILBuilder instead of just an insertion point to the callback.
This makes more sense (given the function names) and simplifies the usages.
It's a NFC.
