dev-libs/check: Fix missing dep on texinfo re bug #613852

dev-libs/check: Fix missing dep on texinfo re bug #613852

Both install and test invoke texinfo, so its important
that texinfo is both present _and_ working.

Lack of build dep on texinfo means that during an empty-world
driven "rebuild all the things" after a perl upgrade,
check will fail either test, or install, due to texinfo
being broken, and portage having no way to ensure texinfo
rebuilds are ordered before check builds.

Bug: https://bugs.gentoo.org/613852

Package-Manager: Portage-2.3.4, Repoman-2.3.2