Clean up indents in `OperatorMsg.chpl` and `BinOp.chpl` and remove unused data types

[1RyanK]

Feature Description
These files have a mix of two space indents and four space indents. I'm transitioning them to entirely two space indents.

I had previously implemented what amounted to as much numpy-style dtype promotion as possible. However, our registration-config.json only uses bool, uint(8), uint(64), int(64), real(64), and bigint. Given that adding more data types would likely put even more pressure on compiler memory, I don't think it's realistic to support several more data types than we currently do. We can also always add the support back in if we get there. Hopefully this also allows me to do some cleanup of the functions, but for now, let's just remove references to these data types.