Move the header file form the global include path include/test to the
module-specific path test/inc.

Change-Id: I72c1f3b420bc387f4f5b9ab75f30f0e8462c1b75
Reviewed-on: https://gerrit.libreoffice.org/51682Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jens Carl <j.carl43@gmx.de>