The call() methods of custom layers are getting hybridized

[khatchad]

That's because tensors are passe to them just like the call() methods of custom Models. Should we:

• Only hybridize call() and __call()__ methods of Models.
• Not hybridize call() and __call()__ methods of Layers.

Either of these would seem to be special cases.

[khatchad]

Even though we are hybridizing call() of layers, it doesn't seem to have a big impact on performance. Maybe it's a little slower but not by much.