<head> <script src="//test.js""></script> <!-- rest of head -->
<head> <script>//<![CDATA[ console.log("Hello 212a."); //]]> </script> <!-- rest of head -->
This is caused by an interaction between Pagespeed and Passenger. Pagespeed attempts to optimize inefficient layouts by performing a litany of optimizations, including inlining external requests that reside on the same domain if the embedded cost is less than the cost of making a subsequent HTTP request to fetch the asset.
Disable Pagespeed (see KB: Disabling PageSpeed) by locating the rule within the document root for the site. Note that Passenger-backed apps do not recursively inherit .htaccess rules as would be the case if the application were not managed by Passenger.