Cycles render tests: Add the option to test with OSL enabled

This commit adds a new cmake variable `WITH_CYCLES_TEST_OSL`
that runs every Cycles test a second time with OSL enabled.

At the moment only CPU OSL is enabled. There are plans to enable
OptiX OSL in the future when stability issues with OptiX OSL
have been resolved.

Some render tests have been blocked from running until we can figure
out a fix. The most notiable being all the Pricincipled BSDF tests
as some of them are failing due to noise differences.

Ref #123012

Pull Request: https://projects.blender.org/blender/blender/pulls/124601

tests/python/modules/render_report.py

@@ -458,6 +458,12 @@ class Report:
 
         return not failed
 
+    def _get_render_arguments(self, arguments_cb, filepath, base_output_filepath):
+        # Each render test can override this method to provide extra functionality.
+        # See Cycles render tests for an example.
+        # Do not delete.
+        return arguments_cb(filepath, base_output_filepath)
+
     def _run_tests(self, filepaths, blender, arguments_cb, batch):
         # Run multiple tests in a single Blender process since startup can be
         # a significant factor. In case of crashes, re-run the remaining tests.
@@ -482,7 +488,7 @@ class Report:
                 if os.path.exists(output_filepath):
                     os.remove(output_filepath)
 
-                command.extend(arguments_cb(filepath, base_output_filepath))
+                command.extend(self._get_render_arguments(arguments_cb, filepath, base_output_filepath))
 
                 # Only chain multiple commands for batch
                 if not batch: