[Distributed] Add ModuleInterface test with generic distributed actor

Author: ktoso

test/ModuleInterface/distributed-actor-generic.swift

@@ -0,0 +1,12 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-emit-module-interface(%t/Library.swiftinterface) %s -module-name Library
+// RUN: %target-swift-typecheck-module-from-interface(%t/Library.swiftinterface) -module-name Library
+// RUN: %FileCheck %s < %t/Library.swiftinterface
+
+// REQUIRES: distributed
+
+import Distributed
+
+@available(SwiftStdlib 6.0, *)
+public distributed actor DAG<ActorSystem> where ActorSystem: DistributedActorSystem<any Codable> {
+}