drill

6e6f789a - DRILL-2400: Part 1: Change cpu cost estimation formula for DrillFilterRelBase. Add testcase for MergeFilter rule.

DRILL-2400: Part 1: Change cpu cost estimation formula for DrillFilterRelBase. Add testcase for MergeFilter rule. Modify costing of Filter. Cost change to Filter. Change to filter costing. Move one test utility method to PlanTestBase.