[Distributed] Minimal test for round tripping through module with DA

Author: ktoso

test/Distributed/distributed_actor_basic.swift

@@ -23,3 +23,4 @@ distributed actor Second {
     try! await first.one(second: self)
   }
 }
+

test/ModuleInterface/distributed_actors.swift

@@ -0,0 +1,31 @@
+// RUN: %empty-directory(%t)
+
+// RUN: %target-swift-emit-module-interface(%t/TestResilient.swiftinterface) %s -module-name TestResilient
+// RUN: %target-swift-typecheck-module-from-interface(%t/TestResilient.swiftinterface) -module-name TestResilient
+// RUN: %FileCheck %s < %t/TestResilient.swiftinterface
+
+// RUN: %target-swift-frontend -compile-module-from-interface -swift-version 5 %t/TestResilient.swiftinterface -o %t/TestResilient.swiftmodule
+// RUN: %target-swift-frontend -emit-module -o /dev/null -merge-modules -swift-version 5  -emit-module-interface-path - %t/TestResilient.swiftmodule -module-name TestResilient | %FileCheck %s
+
+import Distributed
+
+@available(macOS 13.0, *)
+typealias DefaultDistributedActorSystem = LocalTestingDistributedActorSystem
+
+@available(macOS 13.0, *)
+distributed actor CheckMe {
+  distributed func test() {
+    // ...
+  }
+
+}
+
+// CHECK: public struct HasDistributedActors {
+@available(macOS 13.0, *)
+public struct HasDistributedActors {
+  let check: CheckMe
+
+  func test() async throws {
+    try await check.test()
+  }
+}