rt: Disable flaky TestRemoteStop.

Change-Id: I5ab2ce899152d3f8b5a7d201953be6d041deea71
diff --git a/runtime/internal/rt/mgmt_test.go b/runtime/internal/rt/mgmt_test.go
index 0c48e4a..ee38ffc 100644
--- a/runtime/internal/rt/mgmt_test.go
+++ b/runtime/internal/rt/mgmt_test.go
@@ -328,6 +328,7 @@
 // TestRemoteStop verifies that the child shuts down cleanly when sending it
 // a remote Stop rpc.
 func TestRemoteStop(t *testing.T) {
+	t.Skip("This test is flaky, enable it once it is fixed.")
 	ctx, h, appCycle, cleanup := setupRemoteAppCycleMgr(t)
 	defer cleanup()
 	stream, err := appCycle.Stop(ctx)
@@ -337,7 +338,7 @@
 	rStream := stream.RecvStream()
 	expectTask := func(progress, goal int32) {
 		if !rStream.Advance() {
-			t.Fatalf("unexpected streaming error: %q", rStream.Err())
+			t.Fatalf("unexpected streaming error: %v", rStream.Err())
 		}
 		task := rStream.Value()
 		if task.Progress != progress || task.Goal != goal {