Use less-generic names in matview.sql.

The original coding of this test used table and view names like "t",
"tv", "foo", etc.  This tended to interfere with doing simple manual
tests in the regression database; not to mention that it posed a
considerable risk of conflict with other regression test scripts.
Prefix these names with "mvtest_" to avoid such conflicts.

Also, change transiently-created role name to be "regress_xxx" per
discussions about being careful with regression-test role creation.

src/test/regress/expected/rules.out

@@ -1289,6 +1289,14 @@ iexit| SELECT ih.name,
    FROM ihighway ih,
     ramp r
   WHERE (ih.thepath ## r.thepath);
+mvtest_tv| SELECT mvtest_t.type,
+    sum(mvtest_t.amt) AS totamt
+   FROM mvtest_t
+  GROUP BY mvtest_t.type;
+mvtest_tvv| SELECT sum(mvtest_tv.totamt) AS grandtot
+   FROM mvtest_tv;
+mvtest_tvvmv| SELECT mvtest_tvvm.grandtot
+   FROM mvtest_tvvm;
 pg_available_extension_versions| SELECT e.name,
     e.version,
     (x.extname IS NOT NULL) AS installed,
@@ -2251,14 +2259,6 @@ toyemp| SELECT emp.name,
     emp.location,
     (12 * emp.salary) AS annualsal
    FROM emp;
-tv| SELECT t.type,
-    sum(t.amt) AS totamt
-   FROM t
-  GROUP BY t.type;
-tvv| SELECT sum(tv.totamt) AS grandtot
-   FROM tv;
-tvvmv| SELECT tvvm.grandtot
-   FROM tvvm;
 SELECT tablename, rulename, definition FROM pg_rules
 	ORDER BY tablename, rulename;
 pg_settings|pg_settings_n|CREATE RULE pg_settings_n AS

src/test/regress/output/misc.source

@@ -588,7 +588,6 @@ SELECT user_relns() AS user_relns
  arrtest
  b
  b_star
- bb
  box_tbl
  bprime
  brinopers
@@ -648,6 +647,16 @@ SELECT user_relns() AS user_relns
  lseg_tbl
  main_table
  money_data
+ mvtest_bb
+ mvtest_t
+ mvtest_tm
+ mvtest_tmm
+ mvtest_tv
+ mvtest_tvm
+ mvtest_tvmm
+ mvtest_tvv
+ mvtest_tvvm
+ mvtest_tvvmv
  num_data
  num_exp_add
  num_exp_div
@@ -682,7 +691,6 @@ SELECT user_relns() AS user_relns
  stud_emp
  student
  subselect_tbl
- t
  tenk1
  tenk2
  test_range_excl
@@ -699,15 +707,7 @@ SELECT user_relns() AS user_relns
  timestamptz_tbl
  timetz_tbl
  tinterval_tbl
- tm
- tmm
  toyemp
- tv
- tvm
- tvmm
- tvv
- tvvm
- tvvmv
  varchar_tbl
  xacttest
 (132 rows)