IRGen: Shuffle self value for witness method partial applications

Update previous commit's test case for 3.0 difference in substitution list handling

Author: aschwaighofer

test/IRGen/partial_apply_forwarder.sil

@@ -15,10 +15,10 @@ public protocol Observer {
   associatedtype Result
 }
 
-sil hidden @witness_method : $@convention(thin) <S where S : Observable><O where O : Observer, S.Result == O.Result> (@in S) -> @owned @callee_owned (@in O) -> () {
+sil hidden @witness_method : $@convention(thin) <S where S : Observable><O where O : Observer, O.Result == S.Result> (@in S) -> @owned @callee_owned (@in O) -> () {
 bb0(%0 : $*S):
-  %1 = witness_method $S, #Observable.subscribe!1 : $@convention(witness_method) <τ_0_0 where τ_0_0 : Observable><τ_1_0 where τ_1_0 : Observer, τ_0_0.Result == τ_1_0.Result> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
-  %2 = partial_apply %1<S, O, S.Result>(%0) : $@convention(witness_method) <τ_0_0 where τ_0_0 : Observable><τ_1_0 where τ_1_0 : Observer, τ_0_0.Result == τ_1_0.Result> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
+  %1 = witness_method $S, #Observable.subscribe!1 : $@convention(witness_method) <τ_0_0 where τ_0_0 : Observable><τ_1_0 where τ_1_0 : Observer, τ_1_0.Result == τ_0_0.Result> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
+  %2 = partial_apply %1<S, S.Result, O>(%0) : $@convention(witness_method) <τ_0_0 where τ_0_0 : Observable><τ_1_0 where τ_1_0 : Observer, τ_1_0.Result == τ_0_0.Result> (@in τ_1_0, @in_guaranteed τ_0_0) -> ()
   return %2 : $@callee_owned (@in O) -> ()
 }