ysql: Intermittent TestPgRegressAuthorization failure

[tedyu]

Jira Link: DB-4793
https://detective-gcp.dev.yugabyte.com/job/github-yugabyte-db-phabricator%2F117259%2Fartifact%2Fjava%2Fyb-pgsql%2Ftarget%2Fsurefire-reports_org.yb.pgsql.TestPgRegressAuthorization__testPgRegressAuthorization%2Forg.yb.pgsql.TestPgRegressAuthorization-output.txt?class=org.yb.pgsql.TestPgRegressAuthorization&max_lines=3000&name=testPgRegressAuthorization&start_line=108001

Here is the difference in output:

*** /tmp/yb_test.org.yb.pgsql.TestPgRegressAuthorization#testPgRegressAuthorization.20210910221309158275.3872407918/pgregress_output/expected/yb_pg_privileges.out 2021-09-10 22:18:50.351016177 +0000
109076 | --- /tmp/yb_test.org.yb.pgsql.TestPgRegressAuthorization#testPgRegressAuthorization.20210910221309158275.3872407918/pgregress_output/results/yb_pg_privileges.out 2021-09-10 22:18:50.265010412 +0000
109077 | ***************
109078 | *** 290,295 ****
109079 | --- 290,296 ----
109080 | SELECT * FROM atest3; -- fail
109081 | ERROR: permission denied for table atest3
109082 | DELETE FROM atest3; -- ok
109083 | + ERROR: permission denied for table atest3
109084 | -- views
109085 | SET SESSION AUTHORIZATION regress_priv_user3;
109086 | CREATE VIEW atestv1 AS SELECT * FROM atest1; -- ok
109087