Error is thrown if reference image is not present on Android and WebGL

Expected: If reference image doesn't exist, test still runs without the image and produces a new image.

Actual: Error is thrown.

'[Error] Couldn't find reference or base reference image 252_RenderRequest to associate with test case 252_RenderRequest'

Workaround: Have any reference image that could be loaded in for each scene (for example copied from other platforms or under ReferenceImagesBase)