[llm] See what happens if we export with max_seq_len

See if any CI is broken by this.

Author: larryliu0820

extension/llm/export/builder.py

@@ -180,7 +180,7 @@ def _get_dynamic_shape(self) -> Any:
         if self.dynamic_shapes:
             return self.dynamic_shapes
 
-        dim = torch.export.Dim("token_dim", max=self.max_seq_len - 1)
+        dim = torch.export.Dim("token_dim", max=self.max_seq_len)
         if self.enable_dynamic_shape:
             if not self.use_kv_cache:
                 # Only one input argument: tokens