test/py: Fix some pylint warnings in test_ut.py

Tidy up most of these warnings. Remaining are four of these:

   R0914: Too many local variables

which can only by fixed by splitting things into functions, so that is
left for another time.

Part of this change was done by the flynt tool.

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