Fix possible crash in tablesync worker.
Commit
c3afe8cf5a added a new password_required option but forgot that you
need database access to check whether an arbitrary role ID is a superuser.
Commit
e7e7da2f8d fixed a similar bug in apply worker, and this patch
fixes a similar bug in tablesync worker.
Author: Hou Zhijie
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/OS0PR01MB571607F5A9D723755268D36294759@OS0PR01MB5716.jpnprd01.prod.outlook.com