Make configure check for a couple more Perl modules for --enable-tap-tests.

 Make configure check for a couple more Perl modules for --enable-tap-tests.
 
 Red Hat's notion of a basic Perl installation doesn't include Test::More
 or Time::HiRes, and reportedly some Debian installs also omit Time::HiRes.
 Check for those during configure to spare the user the pain of digging
 through check-world output to find out what went wrong.  While we're at it,
 we should also check the version of Test::More, since TestLib.pm requires
 at least 0.87.
 
 In principle this could be back-patched, but it's probably not necessary.
 
 Discussion: https://postgr.es/m/516.1521475003@sss.pgh.pa.us