Render test: Add option to ignore block list

Add a option to ignore Cycles render test black list, controlled via
BLENDER_TEST_IGNORE_BLOCKLIST environment variable.

Useful for testing to see if anything is seriously broken in a test
that's black listed. (E.g. See if some particle rendering tests are
seriously broken on the GPU)

It would be recommened that this be used to test GPU compiler updates.
Or the enablement of certain features like custom curve rendering on
custom BVH.

Pull Request: https://projects.blender.org/blender/blender/pulls/124662

tests/python/modules/render_report.py

@@ -107,7 +107,7 @@ class Report:
         self.fail_percent = 1
         self.engine_name = self.title.lower().replace(" ", "_")
         self.device = device
-        self.blacklist = blacklist
+        self.blacklist = [] if os.getenv('BLENDER_TEST_IGNORE_BLOCKLIST') is not None else blacklist
 
         if device:
             self.title = self._engine_title(title, device)