There are several kinds of scopes at which it is required that an
address be initialized:
(1) the whole function -- for inout argument to the function
(2) the region a coroutine is active -- for an inout yielded by a
coroutine into the function
(3) the region of a memory access -- for a `begin_access [modify]`.
The move checker enforces that they are initialized at that point by
adding instructions at which the field must be live to liveness.
Previously, all such scopes used the end of the function as the point at
which the memory had to have been reinitialized. Here, the relevant end
of scope markers are used instead.
More importantly, here the diagnostic is made to vary--the diagnostic,
that is, that is issued in the face an address not being initialized at
the end of these different kind of scopes.
Following https://github.com/apple/swift/pull/70333, do the same thing for
modify coroutines, marking the result so that we check uses of the result to
ensure it isn't consumed (without being reinitialized).
