Create two new images (vbe0 and vbe1) containing the two types of VBE-OS
setups: with and without an OEM FIT. Put this in a new img/ subdirectory
since the test_ut.py file is getting quite large.
Most of the test is in C, with just the image-setup done in Python.
Enable the test for non-SPL sandbox builds.
Signed-off-by: Simon Glass <sjg@chromium.org>