loadScript should return a singleton promise, or DEFAUL_URL should be configurable library-wise

[veonline]

I've a probelm in my vuejs app due to the async nature of loadScript and loadModules.
When i boot my vue app i bootstrap also the esri library with loadScript({ url: "https://js.arcgis.com/3.22/init.js"}) and in some of my vue components i load modules with something like loadModules(['esri/geometry/geometryEngine'])
If loadScript with the custom version of the library is not completed, loadModules is rejected.
The solution is to provide the same promise instance for every loadScript call or maybe provide a configurable DEFAULT_URL or seti it with the first call of loadScript.

[tomwayson]

Thanks @veonline

This is the same problem that I mention in #51.

As mentioned in that issue, a work around for now is to pass the same options to loadModules(), so:

loadModules(['esri/geometry/geometryEngine'], { url: "https://js.arcgis.com/3.22/init.js"})

I've elevated the priority of these issues.