Add a linter for debug information (-g)

There are some sanity checks we can do.

For example if you see the following Cmm:

unwind Sp = Just Sp + 16;
Sp = Sp + 16;
unwind Sp = Just Sp + 64;

You can tell that it's wrong because it's clear how Sp changed between the two unwind points.

I think this would fit well with the Cmm linter.