ENYO-2778: don't try to parse nested comments

Fix Javascript comment analysis. See https://enyojs.atlassian.net/browse/ENYO-2778

* ENYO-2778: don't try to parse nested comments (HEAD, origin/ENYO-2778, ENYO-2778)

Enyo-DCO-1.1-Signed-off-by: Dominique Dumont <dominique.dumont@hp.com>