Euclidean division of Inf returns NaN

[wsshin]

I think fld(a, b), for example, must return mathematically the same value as floor(a/b). This is the case for most a and b, but fld returns NaN for a = Inf.

julia> VERSION
v"0.7.0-DEV.4465"

julia> floor(Inf/1.0)
Inf

julia> fld(Inf, 1.0)
NaN

I get similar results for other Euclidean division functions cld and div.

Is this an intended behavior?

[wsshin]

Maybe related to #9283.

[vtjnash]

I think this boils down to rem not being computable for this example, which we use as the means to define all of the div:

julia> rem(Inf, 1.0)
NaN

julia> /(Inf, 1.0)
Inf