hysteria2, grpc: fix the use of GetTLSConfig

[dyhkwong]

When reviewing #3162 (comment), I found that hysteria2 and grpc dialer do not fill ServerName with server address if ServerName is not specified. All other dialers use config.GetTLSConfig(tls.WithDestination(dest)) or security.OptionWithDestination{Dest: dest}).

[dyhkwong]

Another issue: If a server uses IP certificate, and tlsSettings.serverName not specified on client side, the client will report error tls: either ServerName or InsecureSkipVerify must be specified in the tls.Config. Client must fill tlsSettings.serverName with the IP to be able to connect. Is it expected behavior or a bug?

[xiaokangwang]

Client must fill tlsSettings.serverName with the IP to be able to connect.

I think it is more or less unintented and could be changed if necessary. Other than contacting https://1.1.1.1 , I don't see a obvious way it could be used.

If such change was necessary, we should have a look at how it impacts SNI .

[xiaokangwang]

Thanks for your contribution. I believe this pull request is ready to be merged before next minor release.