It emerges that some Perl versions before 5.8.9 have a bug with regexps
that use the /m flag and contain "$".  This is the reason why jacana
is still failing on HEAD, and I was able to duplicate the failure on
prairiedog's host.  There's no real need for "$" in these patterns,
since they are already matching through the statement-terminating
semicolons (or matching an explicit \n in some cases).  So just
remove it.

Note: the reason jacana hasn't actually reported any failures in the
last little while is that the way the pg_dump TAP tests are set up, any
failure of this sort results in echoing the entire pg_dump dump output
to stderr.  Since there were about a hundred such failures, that resulted
in a 30MB log file which choked the buildfarm upload script.  There is
room for improvement here :-(.

Per off-list discussion with Andrew and Stephen.