MersenneTwister: hash seeds like for `Xoshiro` (#51436)
This addresses a part of #37165:
> It's common that sequential seeds for RNGs are not as independent as
one might like.
This clears out this problem for `MersenneTwister`, and makes it easy to
add the same feature to other RNGs via a new `hash_seed` function, which
replaces `make_seed`.
This is an alternative to #37766.
