median and median! are type unstable for floats other than Float64

[galenlynch]

On Julia 1.0.1 official, median appears to be type unstable for Float32 inputs. I'm not sure if this is actually a problem.

julia> @code_warntype median(rand(Float32, 3))
Body::Union{Float32, Float64}
750 1 ─ %1 = Statistics.:(:)::Core.Compiler.Const(Colon(), false)                                                                                                                                  │ 
    │   %2 = invoke Statistics._median(_2::Array{Float32,1}, %1::Colon)::Union{Float32, Float64}                                                                                                   │╻ #median#44
    └──      return %2                                                                                                                                                                             │ 

julia> @code_warntype median!(rand(Float32, 3))
Body::Union{Float32, Float64}
...

[StefanKarpinski]

Good catch! Should definitely be fixed. Even if the compiler is smart enough that this isn't a total performance tragedy anymore, there's no reason for a spurious type instabilities like this and we do want to make sure that the result type is fully predictable.

[galenlynch]

Wow that was fast! Thanks!