databases/cego: update 2.52.20 -> 2.52.21

• handle join master predicate in the most optimal way. To show several condition cases, check123.sql has been added to demonstrate the join optimization for different join cases
• fixed some cases for master predicate handling example: plan select cpid from companyview cv where lower(cv.cpname) like '%%' or debnr = 3; shows the execution plan for the query.