Tests: Cycles: Remove OSL-specific displacement test after fix to match SVM

Since commit 175686f2, the behavior of OSL now matches SVM, so instead of this
separate test this is handled by the regular test and the "does OSL match SVM"
checks.

tests/python/cycles_render_tests.py

@@ -53,11 +53,6 @@ BLOCKLIST_OSL = [
     'image_log.blend',
     'image_non_color.blend',
     'image_mapping_udim.blend',
-    # OSL handles bump + displacement differently from SVM. There are OSL variants of these tests
-    'both_displacement.blend',
-    'bump_with_displacement.blend',
-    # Ray portal test uses bump + displacement
-    'ray_portal.blend',
     # TODO: Tests that need investigating into why they're failing, and how to fix that.
     # Noise differences due to Principled BSDF mixing/layering used in some of these scenes
     'render_passes_.*.blend',