LibJS: Implement the CreateListFromArrayLike() abstract operation

We already have two separate implementations of this, so let's do it
properly. The optional value type check is done by a callback function
that returns Result<void, ErrorType> - value type accepted or message
for TypeError, that is.

Userland/Libraries/LibJS/Forward.h

@@ -111,6 +111,7 @@ class Cell;
 class Console;
 class DeferGC;
 class Error;
+class ErrorType;
 class Exception;
 class Expression;
 class Accessor;