Revert "Add basic TAP test setup for pg_upgrade"

Revert "Add basic TAP test setup for pg_upgrade"

This reverts commit f41e56c76e39f02bef7ba002c9de03d62b76de4d.

The build farm client would run the pg_upgrade tests twice, once as part
of the existing pg_upgrade check run and once as part of picking up all
TAP tests by looking for "t" directories.  Since the pg_upgrade tests
are pretty slow, we will need a better solution or possibly a build farm
client change before we can proceed with this.