When a `borrowing` or `consuming` parameter is captured by a closure,
we emit references to the binding within the closure as if it is non-implicitly
copyable, but we didn't mark the bindings inside the closure for move-only
checking to ensure the uses were correct, so improper consumes would go
undiagnosed and lead to assertion failures, compiler crashes, and/or
miscompiles. Fixes rdar://127382105