Fix MSVC-warning about unused variable in tst_qqmlapplicationengine.cpp

Change-Id: I808e56db47d3967f4361cb8b96644834fafb533a
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Fix MSVC-warnings about double to float truncation in QML-tests.

Change-Id: Ie58585ca3555f0f7808b59221a00763cc702863a
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>