hrreport: Gender-related errors

It appears that reporting on gender is now broken in HRSummary. There are a few symptom of this:

1. When creating/editing a report based on HRSummary, the CRM_Report_Form::addGroupBys produces a warning when processing the gender field: "Notice: Undefined index: title in CRM_Report_Form->addGroupBys() (line 899 of /Applications/MAMP/htdocs/sites/all/modules/civicrm/CRM/Report/Form.php)."

2. When creating/editing a report based on HRSummary, the "Gender" option (under "Personal Details") appears without a label.

3. Following a change around Sep 28, the test cases for HRSummary started failing. There were changes in the way core handles gender and pseudoconstants. https://test.civicrm.org/job/CiviHR-master-git/LABEL=test-ubu1204-1,XSUITE=hrreport%25CRM_AllTests/288/

To address this issue, we should ensure that the tests are passing and that the UI shows gender.