Improve MakeDeclaredNamesUnique#ContextualRenameInverter

`ContextualRenameInverter` tries to restore the original names to variables that were previously
renamed by `MakeDeclaredNamesUnique`. This change is a complete rewrite of its implementation.

1. Be smarter about renaming. The old implementation would fail to rename in many cases
   where restoring the original name is perfectly safe. The changes to the unit test demonstrate this.

2. Also do some reformatting to meet our current standards.

I am doing this now in order to enable full normalization renaming in transpile-only mode.
I discovered that the previous algorithm failed to restore names of function parameters,
which broke runtime parameter injection by Angular which depends on the exact parameter names.
The new algorithm successfully restores those parameter names.

PiperOrigin-RevId: 551419411

Author: brad4d