No promotion of integertypes for Dict keys

[ehelle]

Using integers as Dict keys; Int64 numbers doesn't equal Int32 numbers.

julia> mydict = Dict()
Dict{Any,Any}()

julia> a = int32(4)
4

julia> mydict[a] = 45345435
45345435

julia> mydict[4]
ERROR: key not found: 4
in getindex at dict.jl:500

julia> mydict[int64(4)]
ERROR: key not found: 4
in getindex at dict.jl:500

julia> mydict[int32(4)]
45345435

julia> int32(4) == int64(4)
true

[StefanKarpinski]

This is a fairly deep issue, that stems from this:

julia> isequal(int32(4),int64(4))
false

I have a lot of work done towards changing hashing so that it matches == more closely, but it's a tricky problem. Maybe I can find some time this weekend to finish up that work and integrate it with the rest of Julia. It will be a somewhat disruptive change that we can't really add deprecations for.

[JeffBezanson]

dup of #5314