AICC 1st-level children are not rendered

A common AICC 1-element course package (e.g. built with Articulate Presenter) is imported correctly (in some configurations, PHP Strict Standards notices appear) but not shown to the user.

Under the hood the error, on the current 2.6dev is:

PHP Notice:  Undefined offset: 0 in /path/to/mod/scorm/locallib.php on line 1775

i.e. there are no children in the package:

$result->sco = $scoes['scoes'][0]->children[0];

even if the one-AU course is correctly defined by its own descriptors.

Issue found in a post from the Community:

• https://moodle.org/mod/forum/discuss.php?d=228954#p994556