MDEV-32574 main.winservice_basic sporadically fails on buildbot

This commits only adds  --verbose-bootstrap to mysql_install_db.exe
call to have more error information dumped in case of an error.

mysql-test/main/winservice.inc

@@ -21,7 +21,7 @@ exec $sc_exe delete $service_name;
 source include/shutdown_mysqld.inc;
 echo # run mysql_install_db with --service parameter;
 --disable_result_log
-exec $MYSQL_INSTALL_DB_EXE --datadir=$ddir --port=$MASTER_MYPORT --password=$password --service=$service_name -R;
+exec $MYSQL_INSTALL_DB_EXE --datadir=$ddir --port=$MASTER_MYPORT --password=$password --service=$service_name --verbose-bootstrap -R;
 --enable_result_log
 
 echo # Start service;