add missing code-signing step

Author: kavon

test/Distributed/Runtime/distributed_actor_func_calls_remoteCall_remoteChanged_asyncness.swift

@@ -1,6 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend-emit-module -emit-module-path %t/FakeDistributedActorSystems.swiftmodule -module-name FakeDistributedActorSystems -disable-availability-checking %S/../Inputs/FakeDistributedActorSystems.swift
 // RUN: %target-build-swift -module-name main  -Xfrontend -disable-availability-checking -j2 -parse-as-library -I %t %s %S/../Inputs/FakeDistributedActorSystems.swift -o %t/a.out
+// RUN: %target-codesign %t/a.out
 // RUN: %target-run %t/a.out | %FileCheck %s --color --dump-input=always
 
 // REQUIRES: executable_test