Investigate possible map circularity case in builder

[guybedford]

In the case -

builder.config({
        map: {
            'lodash': 'lodash/lodash.js',
            'spark-md5': 'spark-md5/spark-md5.js'
        },
        paths: {
            "app/": "./dist/public/app/"
        },
        packages: {
            '': {
                defaultExtension: 'js'
            },

Apparently this is throwing on no such file.... node_modules/lodash/lodash.js/lodash.js, even with no requires to lodash/lodash.js present at all in the codebase.

We never apply double maps, so it would be worth confirming where this is coming from.

[guybedford]

Fixed in 3378663.

[guybedford]

Released in 0.15.17.