Add macro for maximum statistics target
The number of places where 10000 was hardcoded had grown a bit beyond
the comfort level. Introduce a macro MAX_STATISTICS_TARGET instead.
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Discussion: https://www.postgresql.org/message-id/flat/
d6069765-5971-04d3-c10d-
e4f7b2e9c459%40eisentraut.org