LP:669420 - Wrong result with non-equality ON clause and join_cache_level > 0 and "(flat, BNL join)"

The following query:

SELECT COUNT(table1 .col_int_nokey) FROM t1 table1 JOIN ( t2 table2 JOIN t2 table3 ON table2 .col_int_key AND table3 .pk >= table2 .col_int_key ) ON table3 .col_varchar_key >= table2 .col_varchar_key ;

returns different results when executed in maria-5.3 with join_cache_level = 0 and join_cache_level > 0; Also reproducible in maria-5.3-mwl128 with BKA = off.