ci/bare-metal: Add test phase timeouts to all boards.

ci/bare-metal: Add test phase timeouts to all boards.

This should help with "marge got stuck for an hour and all I got was this
failed job with no results/" when a system intermittently wedges.

This replaces the BM_POE_TIMEOUT ("did we get something on serial in the
last 3 minutes?") that rpi had, in favor of checking that the whole test
job gets through in 20 minutes.

Acked-by: Juan A. Suarez <jasuarez@igalia.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17096>