swift

c508ef56 - Sema: Check conditional availability earlier in conformance checking

Sema: Check conditional availability earlier in conformance checking We would only check conditioanlavailability once we had committed to a best witness. Instead, let's use this information to disambiguate among multiple best witnesses, if we have them. Access control and unconditional unavailability are still only checked once the witness is chosen. Fixes rdar://problem/77259046.