Re-enable contrib/bloom's TAP tests.

These tests were disabled back in 2018 (commit d3c09b9) because of
failures observed in the buildfarm.  I've not been able to reproduce
any failure on longfin's host, though, so I'm curious whether or to
what extent we've fixed the problem.  Let's re-enable it (in HEAD
only) and see what blows up.

Discussion: https://postgr.es/m/2769443.1632773967@sss.pgh.pa.us

Author: tglsfdc

contrib/bloom/Makefile

@@ -16,9 +16,7 @@ PGFILEDESC = "bloom access method - signature file based index"
 
 REGRESS = bloom
 
-# Disable TAP tests for this module for now, as these are unstable on several
-# buildfarm environments.
-# TAP_TESTS = 1
+TAP_TESTS = 1
 
 ifdef USE_PGXS
 PG_CONFIG = pg_config