fix(proguard): Remap method if there's no line number

[loewenheim]

Right now, the logic for remapping a frame is:

• Try to remap the frame with line number if available.
• Otherwise try to remap the frame with params.
• Otherwise don't remap the frame.

But even putting aside the matter of params, this is not what the Python implementation does. It uses 0 as the line number if it's missing.

Therefore, we now do:

• Try to remap the frame with line number if available.
• Otherwise try to remap the frame with params.
• Otherwise try to remap the frame with line number 0.

I'm honestly surprised that remapping a frame with line 0 ever works, but I've seen it happen.

[Swatinem]

I believe I even added an explicit fn to the proguard mapper at one point to try remapping unambiguous method names which does not require a line number.

The 0 fallback is indeed surprising TBH.

[loewenheim]

I updated this to use ProguardMapper::remap_method instead of line 0. I also refactored map_frame into a more functional version with less repetition (in a separate commit), but I may have gone a bit overboard with the galaxy brain style.

[Swatinem]

lets do it