make sure to also assert ScaledDirectories

Summary:
Directories and ScaledDirectories do the same thing, the latter is however
used for backwards compatibility with old theme implementations that do not
know how to handle scaled icons. since our test knows how to handle
scaled icons the two directories are in fact meant to be one long list for
our purposes

Test Plan: test still passes. stringlist now contains both types

Reviewers: broulik

Reviewed By: broulik

Subscribers: kde-frameworks-devel

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D21079