[test] Fix typo in rdar162800185.swift

I meant to use `%t` here.

Author: hamishknight

test/Distributed/rdar162800185.swift

@@ -2,9 +2,9 @@
 // RUN: split-file %s %t
 
 // Make sure we can resolve the conformance to DistributedActor from a secondary.
-// RUN: %target-swift-frontend -c -module-name main -target %target-swift-5.7-abi-triple %t/a.swift %t/b.swift -o %/tmp
-// RUN: %target-swift-frontend -c -module-name main -target %target-swift-5.7-abi-triple -primary-file %t/a.swift %t/b.swift -o %/tmp
-// RUN: %target-swift-frontend -c -module-name main -target %target-swift-5.7-abi-triple %t/a.swift -primary-file %t/b.swift -o %/tmp
+// RUN: %target-swift-frontend -c -module-name main -target %target-swift-5.7-abi-triple %t/a.swift %t/b.swift -o %t/out.o
+// RUN: %target-swift-frontend -c -module-name main -target %target-swift-5.7-abi-triple -primary-file %t/a.swift %t/b.swift -o %t/out.o
+// RUN: %target-swift-frontend -c -module-name main -target %target-swift-5.7-abi-triple %t/a.swift -primary-file %t/b.swift -o %t/out.o
 
 // REQUIRES: concurrency
 // REQUIRES: distributed