Remove bad test cases (inclusive start, inclusive end null)
Remove unused class
Remove unused methods
Fix mixed mode index iteration.

PersistitIndexRow:
- Fix compareTo behavior when underlying arrays sizes don't match
- Allow specification maximum fieldCount
- Always used the given ascending array

IndexCursorMixedOrder:
- Start and end keys always need computed, not just for unique indexes
- Obey the full IndexBound contract
- All key columns need to be in ascending array
- Pass proper bound size and full ascending array when comparing rows

MixedOrderScanStateSingleSegment:
- Remove invalid attempts at enforcing null KeyRange API (handled prior)
- Fix incorrect handling of singleValue (non-last column) segements
merge nathanlws: Fix mixed mode index interation

Merge pull request #1440 from nathanlws/sql-layer/fix-mixed-order-null-bound
https://github.com/FoundationDB/sql-layer/pull/1440