[openmp][lit] Add support to OpenMP lit.cfg for ROCR_VISIBLE_DEVICES env-var

[ronlieb]

Summary

add support for ROCR_VISIBLE_DEVICES similar to name and purpose as CUDA_VISIBLE_DEVICES

[Meinersbur]

LGTM

[JonChesterfield]

Thanks!

openmp/libomptarget/test/lit.cfg

 # -*- Python -*- vim: set ft=python ts=4 sw=4 expandtab tw=79:
 # Configuration file for the 'lit' test runner.
 
 import os
 import lit.formats
 
 # Tell pylint that we know config and lit_config exist somewhere.
 if 'PYLINT_IMPORT' in os.environ:
     config = object()
     lit_config = object()
 
 # Use the CUDA device as suggested by the env
 if 'CUDA_VISIBLE_DEVICES' in os.environ:
     config.environment['CUDA_VISIBLE_DEVICES'] = os.environ['CUDA_VISIBLE_DEVICES']
 
+# Use the ROCR device as suggested by the env
+if 'ROCR_VISIBLE_DEVICES' in os.environ:
+    config.environment['ROCR_VISIBLE_DEVICES'] = os.environ['ROCR_VISIBLE_DEVICES']
+
 # Allow running the tests with omptarget debug output
 if 'LIBOMPTARGET_DEBUG' in os.environ:
     config.environment['LIBOMPTARGET_DEBUG'] = os.environ['LIBOMPTARGET_DEBUG']
 
 if 'OMP_TARGET_OFFLOAD' in os.environ:
     config.environment['OMP_TARGET_OFFLOAD'] = os.environ['OMP_TARGET_OFFLOAD']
 
 def append_dynamic_library_path(name, value, sep):