Add ability to reset all shared stats types in pg_stat_reset_shared()

Add ability to reset all shared stats types in pg_stat_reset_shared()

Currently, pg_stat_reset_shared() can use an argument to specify the
target of statistics to reset, doing nothing for NULL as it is strict.

This patch adds to pg_stat_reset_shared() the possibility to reset all
the stats types already handled in this function rather than do nothing
if the argument value given is NULL or if nothing is specified
(proisstrict is switched to false).  Like previously, SLRUs are not
included in what gets reset.

The idea to use NULL or no argument to control if all the shared stats
already covered by this function should be reset has been proposed by
Andres Freund.

Bump catalog version.

Author: Atsushi Torikoshi
Reviewed-by: Kyotaro Horiguchi, Michael Paquier, Bharath Rupireddy,
Matthias van de Meent
Discussion: https://postgr.es/m/4291a55137ddda77cf7cc5f46e846daf@oss.nttdata.com