Make pytest a bit more verbose

The "-vv" option gives us full untruncated diffs of compared data
strustures.

(cherry picked from commit bcbe34e22d)

bin/tests/system/pytest.ini

@@ -10,7 +10,7 @@
 # information regarding copyright ownership.
 
 [pytest]
-addopts = --tb=short -rA
+addopts = --tb=short -rA -vv
 log_format = %(asctime)s %(levelname)s:%(name)s %(message)s
 log_date_format = %Y-%m-%d %H:%M:%S
 log_cli = 1