alter_table test sometimes failed in parallel mode, because of transient

table name conflict against rangefuncs test.

src/test/regress/expected/alter_table.out

@@ -737,8 +737,8 @@ drop table def_test;
 alter table pg_class drop column relname;
 ERROR:  permission denied: "pg_class" is a system catalog
 -- try altering non-existent table, should fail
-alter table foo drop column bar;
-ERROR:  relation "foo" does not exist
+alter table nosuchtable drop column bar;
+ERROR:  relation "nosuchtable" does not exist
 -- test dropping columns
 create table atacc1 (a int4 not null, b int4, c int4 not null, d int4);
 insert into atacc1 values (1, 2, 3, 4);

src/test/regress/sql/alter_table.sql

@@ -580,7 +580,7 @@ drop table def_test;
 alter table pg_class drop column relname;
 
 -- try altering non-existent table, should fail
-alter table foo drop column bar;
+alter table nosuchtable drop column bar;
 
 -- test dropping columns
 create table atacc1 (a int4 not null, b int4, c int4 not null, d int4);