swift

19918260 - [Protocol checker] Eliminate ordering dependency with "unsatisfied" check.

[Protocol checker] Eliminate ordering dependency with "unsatisfied" check. When checking whether an @objc protocol requirement is considered satisfied by another requirement with the same selector, make sure to use "getWitness" (rather than "hasWitness") to avoid order dependencies in the computation. These are fantastically hard to reproduce in small test cases.