fails:Encoding::Converter.asciicompat_encoding accepts an encoding name as a String argument
fails:Encoding::Converter.asciicompat_encoding coerces non-String/Encoding objects with #to_str
fails:Encoding::Converter.asciicompat_encoding accepts an Encoding object as an argument
fails:Encoding::Converter.asciicompat_encoding returns a corresponding ASCII compatible encoding for ASCII-incompatible encodings
fails:Encoding::Converter.asciicompat_encoding returns nil when the given encoding is ASCII compatible
fails:Encoding::Converter.asciicompat_encoding handles encoding names who resolve to nil encodings
fails:Encoding::Converter.asciicompat_encoding returns nil if called with an encoding it returned previously
