Debugger: Update executable filename from core if possible

Task-number: QTCREATORBUG-10219

Change-Id: Ib17c23c7e8bfdad4f1dbcaf7757fdb130fba2abf
Reviewed-by: Christian Stenger <christian.stenger@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>