Problem with this for years now. Solution is to embed scripts into dll, due to load order.
But please think about it: 2019 soon JQuery is base plugin for many web components, and we still not able to easily include a simple script on the server without embed it or make or custom component.
use jQuery and add <script src="/myTestScript" /> is the base you see in all tutorials in all components based on it.
It should be easier to test or include some file afetr it.
Please you really need to fix that behavior.