MDEV-28782 mariadb-tzinfo-to-sql to work in bootstrap mode

Work around MDEV-28718 for now, but also optimize the interation
of information_schema.SYSTEM_VARIABLES.

Add test case to show that tzinfo data into bootstrap is
desired functionality.

Bug report thanks to Dan Lenski of AWS.

mysql-test/main/bootstrap.result

@@ -34,4 +34,10 @@ name	dl
 EXAMPLE	ha_example.so
 truncate table mysql.plugin;
 # Kill the server
+#
+# MDEV-28782 mariadb-tzinfo-to-sql to work in bootstrap mode
+#
+#
+# End of 10.6 tests
+#
 # restart

mysql-test/main/bootstrap.test

@@ -133,4 +133,30 @@ EOF
 --exec $MYSQLD_BOOTSTRAP_CMD --default-time-zone=Europe/Moscow < $MYSQLTEST_VARDIR/tmp/bootstrap_9969.sql >> $MYSQLTEST_VARDIR/tmp/bootstrap.log 2>&1
 --remove_file $MYSQLTEST_VARDIR/tmp/bootstrap_9969.sql
 
+--echo #
+--echo # MDEV-28782 mariadb-tzinfo-to-sql to work in bootstrap mode
+--echo #
+
+--write_file $MYSQLTEST_VARDIR/tmp/tz.sql
+use test;
+
+create table time_zone                 like mysql.time_zone;
+create table time_zone_leap_second     like mysql.time_zone_leap_second;
+create table time_zone_name            like mysql.time_zone_name;
+create table time_zone_transition      like mysql.time_zone_transition;
+create table time_zone_transition_type like mysql.time_zone_transition_type;
+
+EOF
+--exec $MYSQL_TZINFO_TO_SQL --skip-write-binlog std_data/zoneinfo/GMT GMT 2>/dev/null >> $MYSQLTEST_VARDIR/tmp/tz.sql
+--append_file $MYSQLTEST_VARDIR/tmp/tz.sql
+DROP TABLE time_zone, time_zone_leap_second, time_zone_name, time_zone_transition, time_zone_transition_type;
+EOF
+--exec $MYSQLD_BOOTSTRAP_CMD < $MYSQLTEST_VARDIR/tmp/tz.sql >> $MYSQLTEST_VARDIR/tmp/bootstrap.log 2>&1
+--remove_file $MYSQLTEST_VARDIR/tmp/tz.sql
+
+--echo #
+--echo # End of 10.6 tests
+--echo #
+
+# restore
 --source include/start_mysqld.inc

sql/tztime.cc

@@ -2726,11 +2726,11 @@ static const char *trunc_tables_const=
   "TRUNCATE TABLE time_zone_transition;\n"
   "TRUNCATE TABLE time_zone_transition_type;\n";
 static const char *wsrep_is_on=
-  "select sum(VARIABLE_NAME='wsrep_on' AND SESSION_VALUE='ON')"
-  " from information_schema.SYSTEM_VARIABLES";
+  "select sum(SESSION_VALUE='ON')"
+  " from information_schema.SYSTEM_VARIABLES WHERE VARIABLE_NAME='wsrep_on'";
 static const char *wsrep_cannot_replicate_tz=
-  "select sum(VARIABLE_NAME='wsrep_mode' and GLOBAL_VALUE NOT LIKE @replicate_opt)"
-  " from information_schema.SYSTEM_VARIABLES";
+  "select sum(GLOBAL_VALUE NOT LIKE @replicate_opt)"
+  " from information_schema.SYSTEM_VARIABLES WHERE VARIABLE_NAME='wsrep_mode'";
 
 int
 main(int argc, char **argv)