Re: psql - improve test coverage from 41% to 88%

I think the TestLib.pm changes should be done separately, not together
with the rest of the hacking in this patch.

Mostly, because I think they're going to cause trouble.  Adding a
parameter in the middle of the list may cause trouble for third-party
users of TestLib.  I propose that we make the routines a bit smarter to
cope with the API change: use named parameters instead.  And in order to
do that without having to change existing users of command_check, make
it so that the routine checks whether the parameter is a hashref, and
behave differently.  So when called as in the existing callsites (five
scalar paramters) it behaves as currently.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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