net/http: fill Request.TLS field if underlying conn implements ConnectionState like net/http2

[WeidiDeng]

What version of Go are you using (go version)?

$ go version
go version go1.19 darwin/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env

What did you do?

Using a custom net.Listener to do traffic multiplexing on the same port.
6ccd66 added tls state field for http2 handler, but currently there is no such thing done for stdlib automatically.

Right now in caddy, I'm using ConnContext to associate net.Conn with context and set it myself in http handler, but I'm hoping stdlib will do it automatically.

What did you expect to see?

http.Request.TLS field is automatically set.

What did you see instead?

http.Request.TLS field is not automatically set.

[gopherbot]

Change https://go.dev/cl/440795 mentions this issue: net/http: set tlsState like http2

[seankhliao]

cc @neild