accounts/keystore: fix flaky test (#21703)

* accounts/keystore: add timeout to test to prevent failure on travis

The TestWalletNotifications test sporadically fails on travis.
This is because we shutdown the event collection before all events are received.
Adding a small timeout (10 milliseconds) allows the collector to be scheduled
and to consume all pending events before we shut it down.

* accounts/keystore: added newlines back in

* accounts/keystore: properly fix the walletNotifications test

accounts/keystore/keystore_test.go

@@ -336,7 +336,9 @@ func TestWalletNotifications(t *testing.T) {
 
 	// Shut down the event collector and check events.
 	sub.Unsubscribe()
-	<-updates
+	for ev := range updates {
+		events = append(events, walletEvent{ev, ev.Wallet.Accounts()[0]})
+	}
 	checkAccounts(t, live, ks.Wallets())
 	checkEvents(t, wantEvents, events)
 }