dEQP: Fix non-GTest error logging. Using the non-GTest dEQP targets led to crashes when deferencing a nullptr error logging method. Fix this by skipping platform init if there is a nullptr logError function. Bug: angleproject:2552 Change-Id: I161e35b49f7e9a7592cec968e3540a2e8b625f94 Reviewed-on: https://chromium-review.googlesource.com/1136663 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Luc Ferron <lucferron@chromium.org>