Note that the best solution to this will be to remove the use of SimpleTest entirely. This is quick fix is intended to help us get PHP7 tests running without needing to cross that bridge.
git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@92857 467b73ca-7a2a-4603-9d3b-597d59a354a9