I don't know about heaven and hell; when the OT god was pissed off he would smite the bad guys and have done with it; then in the NT he decided that's not enough we need extremes and permanence, going on to inspire his inner circle to construct the heaven and hell scenarios.
In our mad world there may be a cult out there that endorses suicide, but other than the fringe nuts don't all religions condemn suicide, on the ground that life belongs to its god and not yours to take?
Hindus are forbidden to take their own life under ahimsa (non-violence), so that suicide is violence against the body which is as sinful as murder; Jewish script admonishes early on that its god requires accounting from each for their life blood, Muslim suicides are damned for eternity, and as you say Christianity also prohibits suicide, without explaining why some that actively sought suicide 'by cop' are called martyrs and have been canonised.
Note that suicide reduces the body count, which is a good enough political reason for religions to condemn the act.
While Buddhism is arguably not an organised religion, as it has no god or miracles and reveres a person rather than some spirit, it also views suicide as a negative since it destroys life, and the punishment is that the suicide 'may be' reborn in a negative role because it's previous life ended in that state.