Generally, I would argue the purpose of suicide is to cease to exist, not start over in an afterlife.
I second that: If you think you will still be there after death, and even worse, have to respond to God for your act and live with remorse for the eternity, you certainly will not kill yourself.
The goal of life, in "normal" religions, is to do your best for the afterlife and for that you need as much time as possible on Earth as more time gives more oportunities to do good deeds.
Only "heretic" religion promote Heaven as a good reason to sacrify your life for the great cause.
But we are talking about sects like al-Qaida or something, not true religions.
