Remove code which defines these variables. Remove their usage in
mysqld.cc.

Remove use of these variables in tests. Re-record tests which have
output which depends on the set of system variables.

Remove two tests which only tested these two system variables.

Change-Id: I677a038ee157789a96e4dde8523fa1f717609698
(cherry picked from commit e246a516cf16540eacceccab963f1e6c2f5faecf)

Simple removal worklog. Exempted from no worklog push rule.