function _getUserKeyMapFilePath() {
        if (window.isBracketsTestWindow) {
            return brackets.app.getApplicationSupportDirectory() + "/_test_/" + KEYMAP_FILENAME;
        }
        return _userKeyMapFilePath;
    }
@private

Gets the full file path to the user key map file. In testing environment
a different file path is returned so that running integration tests won't
pop up the error dialog showing the errors from the actual user key map file.

@return {string} full file path to the user key map file.