- implements `airSlice`, `airBitAnd`, `airBitOr`, `airShr`.
- got a basic design going for the `airErrorName` but for some reason it simply returns
empty bytes. will investigate further.
- only generating `.got.zig` entries when not compiling an object or shared library
- reduced the total amount of ops a mnemonic can have to 3, simplifying the logic
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
