Simplify journal client tests
- sort visits by default (there is a test dedicated to dealing with unsorted messagaes from the journal),
- remove "intermediate checks" in several tests: these do not help much but make the code more difficult to read and maintain,
- rename VISIT_STATUSES1 as VISIT_STATUSES_1 to make less prone to being confused with VISIT_STATUSES (which also exists).
Depends on !188 (closed)
Migrated from D4894 (view on Phabricator)