Improve some psql test code

Improve some psql test code

Split psql_like() into two functions psql_like() and psql_fails_like()
and make them mirror the existing command_like() and
command_fails_like() more closely.  In particular, follow the
universal convention that the test name is the last argument.

Discussion: https://www.postgresql.org/message-id/3199e176-424e-1bef-f180-c1548466c2da@enterprisedb.com