wgengine/magicsock: increase test timeout to reduce flakiness

Updates #654. See that issue for a discussion of why
this timeout reduces flakiness, and what next steps are.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

wgengine/magicsock/magicsock_test.go

@@ -812,7 +812,8 @@ func testActiveDiscovery(t *testing.T, d *devices) {
 
 	mustDirect := func(m1, m2 *magicStack) {
 		lastLog := time.Now().Add(-time.Minute)
-		for deadline := time.Now().Add(5 * time.Second); time.Now().Before(deadline); time.Sleep(10 * time.Millisecond) {
+		// See https://github.com/tailscale/tailscale/issues/654 for a discussion of this deadline.
+		for deadline := time.Now().Add(10 * time.Second); time.Now().Before(deadline); time.Sleep(10 * time.Millisecond) {
 			pst := m1.Status().Peer[m2.Public()]
 			if pst.CurAddr != "" {
 				logf("direct link %s->%s found with addr %s", m1, m2, pst.CurAddr)