LibJS: Include <typeinfo> in AST.cpp again

Linus points out that oss-fuzz wants this to be there.

Userland/Libraries/LibJS/AST.cpp

@@ -48,6 +48,7 @@
 #include <LibJS/Runtime/ScriptFunction.h>
 #include <LibJS/Runtime/Shape.h>
 #include <LibJS/Runtime/WithScope.h>
+#include <typeinfo>
 
 namespace JS {