[autoroll] Update vk-gl-cts -> angle roller to use generic pre-upload step

Change-Id: Icecd62675b616fa37b78b8d68df54173a33a1097
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/401219
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
diff --git a/autoroll/config/vk-gl-cts-angle.cfg b/autoroll/config/vk-gl-cts-angle.cfg
index 9b909ef..721c682 100644
--- a/autoroll/config/vk-gl-cts-angle.cfg
+++ b/autoroll/config/vk-gl-cts-angle.cfg
@@ -51,7 +51,12 @@
       }
       child_path:  "third_party/VK-GL-CTS/src"
       child_subdir:  "angle"
-      pre_upload_steps:  ANGLE_CODE_GENERATION
+      pre_upload_commands:  {
+        command:  {
+          command: "python scripts/run_code_generation.py"
+          cwd: "${parent_dir}"
+        }
+      }
       run_hooks:  true
     }
     gerrit:  {