Goal: get to 100% code coverage for SLEEFPirates.jl

[DilumAluthge]

For context, here is the current code coverage:

[giordano]

Might be needed to get CI working at all, as tests have been consistently failing since last August, which isn't exactly a good look.

[chriselrod]

tests have been consistently failing since last August, which isn't exactly a good look.

Anyone who doesn't like the look is more than welcome to address it.