Cleanup: Use RenderReport variation in Cycles render tests

In ea7d07098b, the RenderReport base
class was reworked to work better with test variations.

This commit reworks the Cycles render tests file to use the new
variation system for Hardware Ray tracing and OSL tests, avoiding the
custom system put in place in previous commits.

Pull Request: https://projects.blender.org/blender/blender/pulls/133813

tests/python/modules/render_report.py

@@ -188,6 +188,7 @@ class Report:
 
     def _engine_path(self, path, variation):
         if variation:
+            variation = variation.replace(' ', '_')
             return os.path.join(path, variation.lower())
         else:
             return path