Accordion component performance

[LeoAref]

I was benchmarking my application, and I found that we have a performance problem in the Accordion component:

It's not a big deal so far, but using it in more places will increase the wasted rendering time, I found some issues for refactoring the Accordion component, but I'll try to create small PR to fix that

[layershifter]

There is PR for Accordion refactor #1375, performance improvements are always welcome. However, I will close this issue, because it's a not priority for core team until 1.0 will be reached.

[ghost]

@LeoAref what is that table? Where it come from? Any performance tool?