Looking for the right tool to test if cleartext HTTP protocol is supported by the webserver that runs TLS on port 443.

In other words, I want to check if webserver enforces HTTPS-only for port 443, or will it actually respond to a std HTTP://[fqdn]:443/[uri] request.

Like this:

start with https://example.com/index.html to get the TLS layer going, but then switch to a HTTP GET request http://example.com:443/index.html