[test] add tests for fn:serialize with new option exist:insert-final-newline
[test] add tests for fn:serialize with new option exist:insert-final-newline

dizzzz/exist,adamretter/exist,dizzzz/exist,lcahlander/exist,lcahlander/exist,adamretter/exist,eXist-db/exist,dizzzz/exist,adamretter/exist,adamretter/exist,eXist-db/exist,adamretter/exist,lcahlander/exist,eXist-db/exist,lcahlander/exist,eXist-db/exist,lcahlander/exist,adamretter/exist,dizzzz/exist,dizzzz/exist,eXist-db/exist,dizzzz/exist,eXist-db/exist,lcahlander/exist