- Do call update_used_tables() for new conditions obtained when adding
  outer join's triggered conditions. Correct values of used_tables() are
  now needed for condition pushdown.
- Update test results

mysql-test/suite/pbxt/r/join_outer.result:
  DS-MRR backport:
  - Update test results
sql/sql_select.cc:
  DS-MRR backport: fix buildbot valgrind failures:
  - Do call update_used_tables() for new conditions obtained when adding
    outer join's triggered conditions. Correct values of used_tables() are
    now needed for condition pushdown.