swift234

We need to be very careful in generic specialization of recurisive functions.

We were waiting to delete old apply / try_apply instructions until after
fully specializing all the apply / try_apply in the function. This is
problematic when we have a recursive call and specializing the function
that we're currently processing, since we end up cloning the function
with the old apply / try_apply present.

Rather than doing this, clean up the old apply / try_apply immediately
after processing each one.

Resolves SR-1114 / rdar://problem/25455308.