Move rolenames test out of the core regression tests.

This test script is unsafe to run in "make installcheck" mode for
(at least) two reasons: it creates and destroys some role names
that don't follow the "regress_xxx" naming convention, and it
sets and then resets the application_name GUC attached to every
existing role.  While we've not had complaints, these surely are
not good things to do within a production installation, and
regress.sgml pretty clearly implies that we won't do them.

Rather than lose test coverage altogether, let's just move this
script somewhere where it will get run by "make check" but not
"make installcheck".  src/test/modules/ already has that property.

Since it seems likely that we'll want other regression tests in
future that also exceed the constraints of "make installcheck",
create a generically-named src/test/modules/unsafe_tests/
directory to hold them.

Discussion: https://postgr.es/m/16638.1468620817@sss.pgh.pa.us

src/test/modules/Makefile

@@ -19,6 +19,7 @@ SUBDIRS = \
 		  test_rbtree \
 		  test_rls_hooks \
 		  test_shm_mq \
+		  unsafe_tests \
 		  worker_spi
 
 $(recurse)

src/test/modules/unsafe_tests/.gitignore

@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/

src/test/modules/unsafe_tests/Makefile

@@ -0,0 +1,14 @@
+# src/test/modules/unsafe_tests/Makefile
+
+REGRESS = rolenames
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/unsafe_tests
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif

src/test/modules/unsafe_tests/README

@@ -0,0 +1,8 @@
+This directory doesn't actually contain any extension module.
+
+What it is is a home for regression tests that we don't want to run
+during "make installcheck" because they could have side-effects that
+seem undesirable for a production installation.
+
+An example is that rolenames.sql tests ALTER USER ALL and so could
+have effects on pre-existing roles.

src/test/regress/parallel_schedule

@@ -55,7 +55,7 @@ test: create_index create_index_spgist create_view index_including index_includi
 # ----------
 # Another group of parallel tests
 # ----------
-test: create_aggregate create_function_3 create_cast constraints triggers select inherit typed_table vacuum drop_if_exists updatable_views rolenames roleattributes create_am hash_func errors
+test: create_aggregate create_function_3 create_cast constraints triggers select inherit typed_table vacuum drop_if_exists updatable_views roleattributes create_am hash_func errors
 
 # ----------
 # sanity_check does a vacuum, affecting the sort order of SELECT *

src/test/regress/serial_schedule

@@ -77,7 +77,6 @@ test: typed_table
 test: vacuum
 test: drop_if_exists
 test: updatable_views
-test: rolenames
 test: roleattributes
 test: create_am
 test: hash_func