Revert "UI\PresenterComponent: removed references created by loadStat…

…e() for persistent parameters. [Closes nette/nette#703]"

This reverts commit cda17f4.

See https://forum.nette.org/cs/35528-stejne-pojmenovany-parametr-akce-presenteru-a-persistentni-odlisne-chovani-v-nette-2-0-oproti-aktualnimu#p221742

src/Application/UI/Component.php

@@ -173,9 +173,9 @@ public function loadState(array $params): void
 					));
 				}
 
-				$this->$name = $params[$name];
+				$this->$name = &$params[$name];
 			} else {
-				$params[$name] = $this->$name ?? null;
+				$params[$name] = &$this->$name;
 			}
 		}