We didn't use this code anywhere in the codebase. As such, we probably
should reduce the surface area we support. In the event that we do
in fact require 256 bit words inside of tendermint, we should adapt
the stdlibs' internal word representations, which also handles SIMD.
Inside of the SDK, a separate solution for big ints / larger words
is employed, which uses big ints. This in turn does utilize the stdlibs
SIMD support.