[5.2] refactor tests to use checkForSystemMessage#44772

laoneo merged 2 commits intojoomla:5.2-devjoomla/joomla-cms:5.2-devfrom

heelc29:5.2/system-test/refactor-system-messageheelc29/joomla-cms:5.2/system-test/refactor-system-messageCopy head branch name to clipboard