Commit 0e69f705 introduced code to analyze partitioned table;
however, that code fails to preserve pg_class.relhasindex correctly.
Fix by observing whether any indexes exist rather than accidentally
falling through to assuming none do.

Backpatch to 14.

Author: Alexander Pyhalov <a.pyhalov@postgrespro.ru>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Discussion: https://postgr.es/m/CALNJ-vS1R3Qoe5t4tbzxrkpBtzRbPq1dDcW4RmA_a+oqweF30w@mail.gmail.com