Asynchronous JS downloading issue after upgrading to Brooklyn release

I was using the following code to download the JS files. This script is in a js file(lets say file1.js) which is in a static resource and is included in skuid pages.

function loadJS(file) {

    var jsElm = document.createElement(“script”);

    jsElm.type = “application/javascript”;

    jsElm.src = file;

    document.body.appendChild(jsElm);

}

loadJS("/soap/ajax/38.0/connection.js"); // file2

loadJS("/soap/ajax/38.0/apex.js"); // file 3


Now my expectation is that after file1 is executed, file2 and file3 will download and then on page load functions will be called. This used to work fine until 8.15.15

After the upgrade, its failing. I suspect the files are getting downloaded asynchronously. 

Will appreciate a quick response on this because some of the customer sandboxes have been upgraded to 9.3.3 and they are stuck.

Thanks,
Sneha