Because of a GCC bug we needed to use a functor instead of a constexpr
function. Since we do not support gcc before version 5 any more, this
can be cleaned up now.

R=jkummerow@chromium.org

Bug: v8:9396
Change-Id: I848c5a25e1d5fa44a1497b06826f9a59b93ed695
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1835543Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64127}