HPCC-8939 Fix problems with <ebcdic-string1> IN ('a','b')

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #4083 from ghalliday/issue8939

HPCC-8939 Fix problems with <ebcdic-string1> IN ('a','b')

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>