Debug.assert for missing module name augmentation

[mhegazy]

See details #10522 (comment)

Here is cloneable gist: https://gist.github.com/Ciantic/60e9dbe330922cfc41086e255820df62

$ tsc --version
Version 2.2.0-dev.20161210
$ npm install
$ tsc
...\typescript\lib\tsc.js:1796
                throw new Error("Debug Failure. False expression: " + (message || "") + verboseDebugString);
                ^

Error: Debug Failure. False expression: