CppEditor: add autotest

Add an autotests for follow symbol under cursor in
QObject::connect calls.

Task-number: QTCREATORBUG-10264
Task-number: QTCREATORBUG-10265

Change-Id: Ie72d49476e173e82027a3579fd71ed5f8ac3f95b
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@digia.com>