tests: shell: cover transactions via nft -f using flat syntax

tests: shell: cover transactions via nft -f using flat syntax

This patch covers transactions using the flat syntax representation, eg.

	add table x
	add chain x y { type filter hook forward priority 0; }
	add chain x y { policy drop; }

This also covers things like:

	add element x whitelist { 1.1.1.1 }
	delete element x whitelist { 1.1.1.1 }

The one above may look silly from a human behaviour point of view, but
silly robots may very well behave like this.

These tests require several kernel patches though in order to pass
successfully.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>