Fix the request to get the test accelerator independent of the root from which the test case is run.
Fix the request to get the test accelerator independent of the root from which the test case is run.

EuropeanSpallationSource/openxal,openxal/openxal,EuropeanSpallationSource/openxal,EuropeanSpallationSource/openxal,openxal/openxal,EuropeanSpallationSource/openxal,luxiaohan/openxal-csns-luxh,luxiaohan/openxal-csns-luxh,EuropeanSpallationSource/openxal,openxal/openxal,openxal/openxal,luxiaohan/openxal-csns-luxh,luxiaohan/openxal-csns-luxh,openxal/openxal