fails:Float#rationalize returns self as a simplified Rational with no argument
fails:Float#rationalize simplifies self to the degree specified by a Rational argument
fails:Float#rationalize simplifies self to the degree specified by a Float argument
fails:Float#rationalize raises a FloatDomainError for Infinity
fails:Float#rationalize raises a FloatDomainError for NaN
fails:Float#rationalize raises ArgumentError when passed more than one argument
