Remove moot --unit-test option for mtr in collections

mysql-test/collections/default.daily

 
-perl mysql-test-run.pl --force --timer  --debug-server --parallel=auto --experimental=collections/default.experimental --comment=normal               --vardir=var-normal                                                                  --report-features --skip-test-list=collections/disabled-daily.list --unit-tests
+perl mysql-test-run.pl --force --timer  --debug-server --parallel=auto --experimental=collections/default.experimental --comment=normal               --vardir=var-normal                                                                  --report-features --skip-test-list=collections/disabled-daily.list
 perl mysql-test-run.pl --force --timer  --debug-server --parallel=auto --experimental=collections/default.experimental --comment=n_mix                --vardir=var-n_mix                                  --mysqld=--binlog-format=mixed --skip-test-list=collections/disabled-daily.list
 perl mysql-test-run.pl --force --timer  --debug-server --parallel=auto --experimental=collections/default.experimental --comment=row                --vardir=var-row                                  --mysqld=--binlog-format=row --skip-test-list=collections/disabled-daily.list
 perl mysql-test-run.pl --force --timer  --debug-server --parallel=auto --experimental=collections/default.experimental --comment=ps_row               --vardir=var-ps_row                                 --mysqld=--binlog-format=row     --ps-protocol --skip-test-list=collections/disabled-daily.list

mysql-test/collections/default.push

-perl mysql-test-run.pl --timer --force --parallel=auto --comment=n_mix --vardir=var-n_mix --mysqld=--binlog-format=mixed --experimental=collections/default.experimental --skip-test-list=collections/disabled-per-push.list --unit-tests
+perl mysql-test-run.pl --timer --force --parallel=auto --comment=n_mix --vardir=var-n_mix --mysqld=--binlog-format=mixed --experimental=collections/default.experimental --skip-test-list=collections/disabled-per-push.list
 perl mysql-test-run.pl --timer --force --parallel=auto --comment=ps_row --vardir=var-ps_row --ps-protocol --mysqld=--binlog-format=row --experimental=collections/default.experimental --skip-test-list=collections/disabled-per-push.list
 perl mysql-test-run.pl --timer --force --parallel=auto --comment=embedded --vardir=var-emebbed  --embedded --experimental=collections/default.experimental
 perl mysql-test-run.pl --timer --force --parallel=auto --comment=rpl_binlog_row --vardir=var-rpl_binlog_row  --suite=rpl,binlog --mysqld=--binlog-format=row --experimental=collections/default.experimental --skip-test-list=collections/disabled-per-push.list