HPCC-8485 result_lib.xslt not escaping some xml strings

When building preliminary node-set some data elements were not marked
for escaping of values.

Signed-off-by: Anthony Fishbeck <Anthony.Fishbeck@lexisnexis.com>
Merge pull request #3839 from afishbeck/escape_column_xml8485

HPCC-8485 result_lib.xslt not escaping some xml strings

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>