fails:Kernel#BigDecimal when interacting with Rational has the expected precision on the LHS
fails:Kernel#BigDecimal when interacting with Rational has the expected maximum precision on the LHS
fails:Kernel#BigDecimal when interacting with Rational BigDecimal precision is the number of digits rounded up to a multiple of nine
fails:Kernel#BigDecimal when interacting with Rational BigDecimal maximum precision is nine more than precision except for abnormals
fails:Kernel#BigDecimal when interacting with Rational BigDecimal(Rational, BigDecimal.precs[0]) produces the result we expect
fails:Kernel#BigDecimal with exception: false returns nil for invalid strings
