fails:Complex#coerce returns an array containing other and self as Complex when other is an Integer
fails:Complex#coerce returns an array containing other and self as Complex when other is a Float
fails:Complex#coerce returns an array containing other and self as Complex when other is a Bignum
fails:Complex#coerce returns an array containing other and self as Complex when other is a Rational
fails:Complex#coerce raises a TypeError when other is a String
