Add an assert to Map_NestedLoops to make explict a data loss failure.
Remove the logging information added in previous commits.
Unwrap SQLException when checking if retryable
Switch utf8_bin to ucs_binary
merge nathanlws: Unwrap SQLException when checking if error is retryable

Merge pull request #1446 from nathanlws/sql-layer/retry-large-sort-it
https://github.com/FoundationDB/sql-layer/pull/1446
merge tjoneslo: Add map nested assert

Merge pull request #1445 from tjoneslo/sql-layer/add-map-nested-assert
https://github.com/FoundationDB/sql-layer/pull/1445