psql: Rework TAP routine psql_fails_like() to define WAL sender context
The routine was coded so as a WAL sender was always used, state required
only for one failure test related to START_REPLICATION. This test is
changed so as a WAL sender is used by passing a replication option to
psql_fails_like(), instead of forcing the use of a WAL sender for all
the tests.
This has come up as useful in the context of a separate bug fix where
we are looking at extending tests for some failure scenarios. These
tests need to happen in the context of a normal backend, and not a WAL
sender where the extended query protocol cannot be used.
Discussion: https://postgr.es/m/aAXkJIOildLUA7vQ@paquier.xyz