dEQP: search for the data directory relative to the exe path. BUG=580045 Change-Id: I58bfa9ab6766eaae756b3c0f4d28f545e86d543b Reviewed-on: https://chromium-review.googlesource.com/327306 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>