[CI/Build] Reorganize models tests (#17459)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

vllm/config.py

@@ -1043,8 +1043,10 @@ class ModelConfig:
         if self.is_attention_free:
             return 0
 
-        if hasattr(self.hf_text_config, "head_dim"):
+        # NOTE: Some configs may set head_dim=None in the config
+        if getattr(self.hf_text_config, "head_dim", None) is not None:
             return self.hf_text_config.head_dim
+
         # FIXME(woosuk): This may not be true for all models.
         return (self.hf_text_config.hidden_size //
                 self.hf_text_config.num_attention_heads)