HPCC-9217 Remove legacy implementations of editdistance functions

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4320 from ghalliday/issue9217

HPCC-9217 Remove legacy implementations of editdistance functions

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>