Description

Windows OpenSSH doesn't support multiplexing PowerShell/Win32-OpenSSH#405 because of that Docker just needs to constantly open SSH sessions to the remote server until it runs out of connections.

I was thinking that for Windows (and to make it easier for other OS's users so they don't have to update their .ssh/config file) pool the connection of the SSH contexts so it only uses a single SSH connection for everything.

This would solve issues like moby/buildkit#4991
and should really be part of the effort in #46821