change argument order for rand! (fix #8246)

The API to fill randomly an array A is changed
from rand!([rng], [::Range], A) to rand!([rng], A, [::AbstractArray]).
Enabling [::AbstractArray] instead of only [::Range] depended on choosing first
the argument order.
Merge pull request #9092 from JuliaLang/rf/randbang-arg-order

change argument order for rand! (fix #8246)