Revert "qmldesigner: compile fix"

This reverts commit f4248e2cac.
It's not needed anymore as code using it is gone.

src/plugins/qmldesigner/core/model/texttomodelmerger.cpp

@@ -45,7 +45,6 @@
 #include <QDeclarativeEngine>
 #include <QSet>
 #include <private/qdeclarativedom_p.h>
-#include <typeinfo>
 
 using namespace QmlJS;
 using namespace QmlJS::AST;