FindBoost: Revert "Simplify search in lists."
Revert commit v3.9.0-rc1~41^2 (FindBoost: Simplify search in lists, 2017-04-23). It regressed the module by exposing issue #17257, but the fix for that issue is not suitable for inclusion in a patch release. It is simplest to revert the commit until the larger problem can be addressed. Fixes: #17252