xtstat crashes with segmentation fault on startup if max_pbxt_threads exceeded

PBXT 1.0.09d

#0 0x00002b5223337d75 in mysql_fetch_row (res=0x0) at client.c:2905
#1 0x0000000000403157 in main (argc=4, argv=0x7fff877f7158)
    at xtstat_xt.cc:685

It happens if xtstat is started without --database option or with --database=information_schema. If it is run with --database=pbxt, it gets stuck at
Got error -1 from storage engine
Reconnecting...

but does not crash.

The behavior changed from the previous 1.0.09, where xtstat would always end up in the 'Reconnecting' state.
Note: there was an apparently related fix for bug:431240.

To reproduce:

- start MySQL server with pbxt_max_threads=20 or less;
- from a client connection, run

set global event_scheduler=ON;
use test;
drop table if exists t1;
drop event if exists ev1;
drop event if exists ev2;
drop event if exists ev3;
drop event if exists ev4;
drop event if exists ev5;
create table t1 ( i int ) engine = pbxt;
drop event if exists ev;
delimiter |
create event ev1 on schedule every 1 second do begin insert into test.t1 values (1); end|
create event ev2 on schedule every 1 second do begin insert into test.t1 values (2); end|
create event ev3 on schedule every 1 second do begin insert into test.t1 values (3); end|
create event ev4 on schedule every 1 second do begin insert into test.t1 values (4); end|
create event ev5 on schedule every 1 second do begin insert into test.t1 values (5); end|
delimiter ;
lock tables t1 write;
select sleep(5);

- do not close client connection;
- attempt to start xtstat without --database option or with --database=information_schema