tests: retry fetching when record added but no results
tests: retry fetching when record added but no results

In test_work_simple and test_work_simple_xml:
tests will retry fetching added record, if the
addition returned HTTP 200, but no record is
returned.

Signed-off-by: Szymon Łopaciuk <3174a6013562e53794ada556354772ce9378e569@cern.ch>

ORCID/python-orcid