How to simulate non-SNI browsers (without SNI support)?

You can use the most commonly used SSL library, OpenSSL. Windows binaries are available to download.

openssl s_client -connect domain.com:443 command serves very well to test SSL connection from client side. It doesn't support SNI by default. You can append -servername domain.com argument to enable SNI.

If you are using OpenSSL 1.1.0 or earlier version, use openssl s_client -connect $ip:$port, and OpenSSL wouldn't enable the SNI extension

If you are using OpenSSL 1.1.1, you need add -noservername flag to openssl s_client.