libnftables: keep evaluating until parser_max_errors

libnftables: keep evaluating until parser_max_errors

Bail out after parser_max_errors has been reached, eg.

 # nft -f /tmp/errors.nft
 /tmp/errors.nft:1:23-23: Error: syntax error, unexpected newline
 filter input tcp dport
                       ^
 /tmp/errors.nft:2:24-26: Error: datatype mismatch, expected internet network service, expression has type Internet protocol
 filter input tcp dport tcp
              ~~~~~~~~~ ^^^
 /tmp/errors.nft:3:24-26: Error: datatype mismatch, expected internet network service, expression has type Internet protocol
 filter input tcp sport udp
              ~~~~~~~~~ ^^^

Fixes: f211921e25e6 ("src: perform evaluation after parsing")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>