Php7 IIFE syntax parsing

Added parsing support for php7 iife syntax.

Reviewers: kfunk, #kdevelop, mwolff

Reviewed By: #kdevelop, mwolff

Subscribers: kdevelop-devel

Tags: #kdevelop
BUG: 370515
Differential Revision: https://phabricator.kde.org/D4391

(cherry picked from commit 2bcdaa11)