Improve the query planner by reducing the estimated number of output rows

Improve the query planner by reducing the estimated number of output rows
for each stage of a join if there are LIKE, GLOB, REGEXP, or MATCH
constraints on the table where the pattern string is a constant.  The
reduction in the output row estimate is proportional to the length of
the pattern string.

FossilOrigin-Name: 6852843e6aa23051de0884593ce64b96a16f16c4d63b222bd324297581f7cf75