[pipeline] Llama pipeline (#4205)

* bloom policy

* llama pipeline forward and tests

* fix the output and attention_mask

* fix name

* bind argument to policy

* Revert "bloom policy"

This reverts commit 8dee68a0a2.

This policy should be revert and copied to feature/bloom

* revert the bloom changes

* cancel unneeded inputs

* gpt

tests/kit/model_zoo/transformers/gpt.py

@@ -52,7 +52,7 @@ loss_fn_for_gpt2_model = lambda x: x.last_hidden_state.mean()
 loss_fn = lambda x: x.loss
 
 config = transformers.GPT2Config(n_layer=2,
-                                 n_head=4,
+                                 n_head=2,
                                  vocab_size=50258,
                                  attn_pdrop=0,
                                  embd_pdrop=0,