added an arch without trunk3 for code detection

Summary:
Pull Request resolved: https://github.com/facebookresearch/d2go/pull/670

registered a new arch without trunk3 since our trunk2 model has better quality.

Reviewed By: huiyujie

Differential Revision: D59613942

fbshipit-source-id: 605e8925bfcd91d8a966303d9c0a3b4f56a9a0c7

d2go/modeling/modeldef/modeldef.py

@@ -538,6 +538,14 @@ MODEL_ARCH_BUILTIN = {
         "kpts": TINY_DS_UPSAMPLE_HEAD_STAGES,
         "basic_args": _BASIC_ARGS,
     },
+    "FBNetV3_B_light_large_3layers": {
+        "trunk": FBNetV3_B_light_no_se[0:3],
+        "rpn": [[_repeat_last(FBNetV3_B_light_no_se[3])]],
+        "bbox": SMALL_BOX_HEAD_STAGES,
+        "mask": SMALL_DS_UPSAMPLE_HEAD_STAGES,
+        "kpts": LARGE_UPSAMPLE_HEAD_D21_STAGES,
+        "basic_args": _BASIC_ARGS,
+    },
     "FBNetV3_B_light_large": {
         "trunk": FBNetV3_B_light_no_se[0:4],
         "rpn": [[_repeat_last(FBNetV3_B_light_no_se[3])]],