Make -w wipe a standalone flag.

testing/iossim/iossim.mm

Index: testing/iossim/iossim.mm
diff --git a/testing/iossim/iossim.mm b/testing/iossim/iossim.mm
index 58890ab5ad815b0c3fb2236c7825b88cc676f744..3c1e353eeae30918d9da25c6deb7af088068e7f9 100644
--- a/testing/iossim/iossim.mm
+++ b/testing/iossim/iossim.mm
@@ -336,6 +336,13 @@ int main(int argc, char* const argv[]) {
     exit(kExitSuccess);
   }
 
+  KillSimulator();
+  if (wants_wipe) {
+    WipeDevice(udid);
+    printf("Device wiped.\n");
+    exit(kExitSuccess);
+  }
+
   // There should be at least one arg left, specifying the app path. Any
   // additional args are passed as arguments to the app.
   if (optind < argc) {
@@ -364,11 +371,6 @@ int main(int argc, char* const argv[]) {
     exit(kExitInvalidArguments);
   }
 
-  KillSimulator();
-  if (wants_wipe) {
-    WipeDevice(udid);
-  }
-
   RunApplication(app_path, xctest_path, udid, app_env, cmd_args);
   KillSimulator();
   return kExitSuccess;