pg_upgrade: Check for the expected error message in TAP tests.

pg_upgrade: Check for the expected error message in TAP tests.

Since pg_upgrade prints its error messages on stdout, we can't use
command_fails_like() to check if it fails for the right reason. This
commit uses command_checks_all() in pg_upgrade TAP tests to check the
exit status and stdout, enabling proper verification of error
reasons.

Author: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://postgr.es/m/87tt8h1vb7.fsf@wibble.ilmari.org