GSB: Remove obsolete hack for well-founded requirements
GSB: Remove obsolete hack for well-founded requirements

This used to be necessary to handle this case:

    protocol P1 {
      associatedtype A
    }

    protocol P2 {
      associatedtype A : P1
    }

    func foo<T : P1>(_: T) where T.A : P2,  T.A.A == T {}

We don't want to mark 'T : P1' as redundant, even though it could
be recovered from T.A.A, because it uses the requirement T.A, and
we cannot recover the type metadata for T.A without the witness
table for T : P1.

Now this is handled via a more general mechanism, so we no longer
need this hack.

hooman/swift,atrick/swift,parkera/swift,rudkx/swift,xwu/swift,gregomni/swift,benlangmuir/swift,glessard/swift,roambotics/swift,atrick/swift,roambotics/swift,parkera/swift,JGiola/swift,gregomni/swift,gregomni/swift,ahoppen/swift,hooman/swift,JGiola/swift,atrick/swift,parkera/swift,benlangmuir/swift,xwu/swift,parkera/swift,atrick/swift,rudkx/swift,JGiola/swift,parkera/swift,benlangmuir/swift,roambotics/swift,roambotics/swift,parkera/swift,apple/swift,benlangmuir/swift,atrick/swift,apple/swift,JGiola/swift,gregomni/swift,xwu/swift,glessard/swift,glessard/swift,tkremenek/swift,tkremenek/swift,JGiola/swift,roambotics/swift,parkera/swift,tkremenek/swift,tkremenek/swift,hooman/swift,rudkx/swift,xwu/swift,xwu/swift,glessard/swift,benlangmuir/swift,JGiola/swift,rudkx/swift,tkremenek/swift,xwu/swift,ahoppen/swift,roambotics/swift,gregomni/swift,gregomni/swift,apple/swift,apple/swift,glessard/swift,glessard/swift,ahoppen/swift,rudkx/swift,apple/swift,apple/swift,hooman/swift,hooman/swift,hooman/swift,tkremenek/swift,tkremenek/swift,rudkx/swift,ahoppen/swift,parkera/swift,ahoppen/swift,xwu/swift,hooman/swift,ahoppen/swift,benlangmuir/swift,atrick/swift