boot: test: Add a test for the VBE OS flow

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.

Signed-off-by: Simon Glass <sjg@chromium.org>

test/py/test.py

@@ -12,6 +12,10 @@ import os.path
 import sys
 import pytest
 
+# Bring in the U-Boot libraries
+our_path = os.path.dirname(os.path.realpath(__file__))
+sys.path.append(os.path.join(our_path, '../../tools'))
+
 if __name__ == '__main__':
     # argv; py.test test_directory_name user-supplied-arguments
     args = [os.path.dirname(__file__) + '/tests']