MetaFixer fails to fix overlaps when multiple tables have overlaps

MetaFixer fails to fix overlaps when multiple tables have overlaps
Steps to reproduce from UT.

1. Create table t1 and t2 with split keys, ["bbb", "ccc", "ddd", "eee"]
2. Create extra region in both t1 and t2 with start key "bbb" and end key "ddd"
3. Run catalog janitor, It will report total 4 overlaps, 2 from each table.
4. Run MetaFixer, wait for merges to finish.
5. Run the catalog janitor again and verify report, there should not be any overlap
6. Overlap still exists. Reproduced!!!

Analysis.

• When I run the same scenario for just one table t1, overlaps are fixed successfully.
• Seems problem with MetaFixer#calculateMerges.
• I think merges should be calculated within a table. Across the table merge does not have significance.