s4:torture/smb2: split replay_smb3_specification into durable handle and multichannel

s4:torture/smb2: split replay_smb3_specification into durable handle and multichannel

It's better to have durable handles and multichannel tested separate:
1. we test both cases in the server
2. it makes it easier to deal with knownfail entries if only one
   of these features is active on the server.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Guenther Deschner <gd@samba.org>