This makes the function constexpr and implements it for arbitrary
unsigned integer types (up to 64 bits, but this can be extended if
needed).

R=mstarzinger@chromium.org

Bug: v8:6600, v8:6921
Change-Id: I86d427238fadd55abb5a27f31ed648d4b02fc358
Reviewed-on: https://chromium-review.googlesource.com/718457
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48696}