Zabbix

..F....... [ZBX-18425] fixed browser error "updateItemTestBtn is not defined"

Merge in ZBX/zabbix from feature/ZBX-18425-5.1 to master

* commit 'bfd48903744f9d996d70538151db62f8229b3422':
  .......... [ZBX-18425] added wait for page to load after dropdown selection
  .......... [ZBX-18425] added sleep function due to unstable autotest execution
  .......... [ZBX-18425] fixed Selenium framework, changed wait for selected option in dropdown
  .......... [ZBX-18425] added additional waits in Selenium test
  .D........ [ZBX-18425] added change log entry
  ..F....... [ZBX-18425] fixed browser errors "updateItemTestBtn is not defined"