Port applyAttributeBindings to attr nodes

[mixonic]

applyAttributeBindings is slow. It should be ported to use streams and attr nodes.

[oneeman]

I'll give this and #9922 a shot. From what I've seen it looks like doing them one at a time might be messier than together, since attribute nodes need to be created after the element has been generated whereas under the old way the bindings are set up before the buffer.generateElement() call (correct me if I'm confused here).

[mixonic]

@oneeman I wonder if this might not be appropriate any more, apologies. I'm working on splitting attr nodes into an attribute morph object in HTMLBars, and an attrview object that is managed via the renderer. I believe this is required in order to port attribute bindings to a shared system with bind-attr and htmlbars-syntax attrs.

[oneeman]

No worries, I've just been familiarizing myself with the view layer, so it's all good.

[rwjblue]

@mixonic - I believe that this is something you are working on currently, c/d?

[mixonic]

I have this underway with just a few more tests failing. It is a large number of changes.