Introducing the idea of extractVariant

In previous PRs we introduced the idea of printVariant in order to avoid extra processing on Prettier's side. This is the next step of that idea where we extract the variant at the initiation moment and ignore the PolymorphicNode. This adds the following benefits:

• less navigation through the tree when querying the state of a child or a parent whenever we happen to navigate through a PolymorphicNode
• querying the state of a PolymorphicNode is now removed
• less and cleaner code and smaller build size
• there is a noticeable improvement in the speed

The downside is that the use of variants is used all around the codebase so the full change has been separated in individual commits (all of them will pass the CI) with a final cleanup commit.

All of these commits will follow the same idea but some impact the code much deeper than others so I'll be making PRs slowly so the changes can be individually reviewed.

This PR

We skip ArgumentsDeclaration, remove all variant queries, and remove all calls to printVariant for this particular node.