Revert Test::Builder changes in prep for 5.21.3

This reverts commit 6bdb88770f849c47b5c09e733ac460ce3e9dbc97
and commit 59c96aebdd56baf5d1979103046b1c6d4e308aa2, which
are causing the test suite to run much slower and which are
failing on some platforms.

http://nntp.perl.org/group/perl.perl5.porters/218678 has
further details, with RT 122538 being the ticket number.