[Distributed] Don't drop dist get accessors from witness tables.

This actually manifested as an pointer auth crash, but the real reason
being is that we messed up the order of elements in the witness table.
If we'd skip the accessor like this, the types we sign/auth with would
no longer align and manifest in a crash.

There is no real reason to skip this entry so we just bring it back, and
avoid making this special in any way.

This unlocks a few tests as well as corrects any distributed+protocol
use where a requirement distributed var was _followed by_ other
requirements.

resolves rdar://125628060

test/Distributed/Runtime/distributed_actor_localSystem_distributedProtocol.swift

@@ -14,9 +14,6 @@
 // rdar://90373022
 // UNSUPPORTED: OS=watchos
 
-// rdar://125628060
-// UNSUPPORTED: CPU=arm64e
- 
 import Distributed
 
 @Resolvable