[gardening] Use a higher level method that describes what a piece of code is doing instead of source inlining it.

Author: gottesmm

lib/SILGen/SILGenConcurrency.cpp

@@ -50,7 +50,7 @@ static void setExpectedExecutorForParameterIsolation(SILGenFunction &SGF,
                                              ActorIsolation actorIsolation) {
   auto loc = RegularLocation::getAutoGeneratedLocation(SGF.F.getLocation());
   ManagedValue actorArg;
-  if (actorIsolation.getActorInstanceParameter() == 0) {
+  if (actorIsolation.isActorInstanceForSelfParameter()) {
     ManagedValue selfMV;
     auto selfArg = SGF.F.getSelfArgument();
     if (selfArg->getOwnershipKind() == OwnershipKind::Guaranteed) {