Conflict between regression tests namespace & transactions due to recent changes

Hello, hackers!

When running tests for version 15, we found a conflict between 
regression tests namespace & transactions due to recent changes [1].

diff -w -U3 .../src/test/regress/expected/transactions.out 
.../src/bin/pg_upgrade/tmp_check/results/transactions.out
--- .../src/test/regress/expected/transactions.out ...
+++ .../src/bin/pg_upgrade/tmp_check/results/transactions.out ...
@@ -899,6 +899,9 @@

  RESET default_transaction_read_only;
  DROP TABLE abc;
+ERROR:  cannot drop table abc because other objects depend on it
+DETAIL:  view test_ns_schema_2.abc_view depends on table abc
+HINT:  Use DROP ... CASCADE to drop the dependent objects too.
  -- Test assorted behaviors around the implicit transaction block 
created
  -- when multiple SQL commands are sent in a single Query message.  
These
  -- tests rely on the fact that psql will not break SQL commands apart 
at a
...

IIUC the conflict was caused by

+SET search_path to public, test_ns_schema_1;
+CREATE SCHEMA test_ns_schema_2
+       CREATE VIEW abc_view AS SELECT a FROM abc;

because the parallel regression test transactions had already created 
the table abc and was trying to drop it.

ISTM the patch diff.patch fixes this problem...

[1] 
https://github.com/postgres/postgres/commit/dbd5795e7539ec9e15c0d4ed2d05b1b18d2a3b09

-- 
Marina Polyakova
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company