Previously presence of both [class] and [className] bindings on an element was treated as compiler error (implemented in 6f203c9575). Later, the situation was improved to actually allow both bindings to co-exist (see a153b61098), however the compiler check was not removed completely. The only situation where the error is thrown at this moment is when static (but with interpolation) and bound `class` attributes are present on an element, for ex.:
```
<div class="{{ one }}" [class]="'two'"></div>
```
In the current situation the error is acually misleading (as it refers to `[className]`).
This commit removes the mentioned compiler check as obsolete and makes the `class` and `style` attribute processing logically the same (the last occurrence is used to compute the value).
PR Close#41254
3a55698402