Verify config saves survive cancellation of their submitting scope

tools/chatgui-android/app/src/test/java/com/utun/chat/data/ConfigFileStoreTest.kt

@@ -9,6 +9,7 @@ import java.util.concurrent.atomic.AtomicBoolean
 import java.util.concurrent.atomic.AtomicInteger
 import java.util.concurrent.atomic.AtomicReference
 import kotlinx.coroutines.CoroutineStart
+import kotlinx.coroutines.Deferred
 import kotlinx.coroutines.cancelAndJoin
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.runBlocking
@@ -52,8 +53,11 @@ class ConfigFileStoreTest {
         val first = store.submit("blocked") { entered.countDown(); check(release.await(2, TimeUnit.SECONDS)) }
         try {
             assertTrue(entered.await(2, TimeUnit.SECONDS))
-            val save = store.submit("save") { replace(file, "complete") }
-            val screen = launch(start = CoroutineStart.UNDISPATCHED) { save.await() }
+            lateinit var save: Deferred<Unit>
+            val screen = launch(start = CoroutineStart.UNDISPATCHED) {
+                save = store.submit("save") { replace(file, "complete") }
+                save.await()
+            }
             screen.cancelAndJoin()
             assertFalse(save.isCancelled)
             release.countDown()