tools: don't check software rendering before GLES helper

A regression from 51d1e181 -- the code
is currently skipping GLES checks when software rendering is in use.

Instead, it should first try to use the GLES helper, or animations will
be disabled on devices such as ARM machines, which are not compatible
with desktop GL.

https://bugzilla.gnome.org/show_bug.cgi?id=768292