Clean test_rls_hooks module

This module isn't an extension and doesn't need to be preloaded.
Adjust the Makefile and remove the extraneous .control and .conf
files accordingly.

Discussion: https://postgr.es/m/43bcaaab-077e-cebe-35be-3cd7f2633449@dunslane.net

src/test/modules/test_rls_hooks/Makefile

@@ -6,14 +6,7 @@ OBJS = \
 	test_rls_hooks.o
 PGFILEDESC = "test_rls_hooks - example use of RLS hooks"
 
-EXTENSION = test_rls_hooks
-# DATA = test_rls_hooks--1.0.sql
-
 REGRESS = test_rls_hooks
-REGRESS_OPTS = --temp-config=$(top_srcdir)/src/test/modules/test_rls_hooks/rls_hooks.conf
-# Disabled because these tests require "shared_preload_libraries=test_rls_hooks",
-# which typical installcheck users do not have (e.g. buildfarm clients).
-NO_INSTALLCHECK = 1
 
 ifdef USE_PGXS
 PG_CONFIG = pg_config

src/test/modules/test_rls_hooks/rls_hooks.conf

@@ -1 +0,0 @@
-shared_preload_libraries = test_rls_hooks

src/test/modules/test_rls_hooks/test_rls_hooks.control

@@ -1,4 +0,0 @@
-comment = 'Test code for RLS hooks'
-default_version = '1.0'
-module_pathname = '$libdir/test_rls_hooks'
-relocatable = true