Unify Babel & SWC

After the latest commits to this project I'm really hooked to improve it further.

One aspect that I noticed that bugs me is that when you switch from Babel to SWC or vice versa, there will be changes for the names of the variables (with and without `displayNames`).

I have a branch that changes the tests so that the interoperability is checked and I started with changing the babel plugin logic (to be the same as in SWC), because I think the visual names in SWC are much better.

I wanted to ask if this direction is generally a good idea or do you see issues?

Start by reviewing the existing Babel plugin logic and the branch's interoperability tests, then compare variable-name behavior with SWC for cases with and without displayNames. Done would require an agreed direction for unifying the naming behavior and tests that verify Babel and SWC interoperability.

Written by the indexing model from the issue text.