Zabbix

..F....... [DEV-4931] reduced the number of recursive calls while building the expression tree

* commit '0aff2564d7ce0f2119e987d2692bbbcc5f47e4bf':
  ..F....... [DEV-4931] fixed a corner case with deeply nested expressions
  ..F....... [DEV-4931] add permission check for trigger expression edit and test
  ..F....... [DEV-4931] reduced the number of recursive calls while building the expression tree