The OP never said anyone was contemplating doing this. It just asked a simple what if. And while no you don't want to condone it, are you going to lie just to avoid the unintended appearance of condoning it? Yes suicide is self murder, murder is a sin, sin keeps us from God. But then God paid the fine for us, so we can again get back to Him despite our many sins. This one included.
The one, and only qualifier for "getting in" is accepting Christ. That's it. In the eternal, once we accept Christ, sin has no power over us. It's a done deal. But in the here and now, there are consequences. If you submit to a spiritual authority in sin, you're submitted to that spiritual authority. Now, most every other sin has the luxury of our being able to later confess and repent of it, breaking that submission. But the sin of self murder - not so much. That's an irrevocable act, assuming you're successful, which a huge percentage of attempts are not. They most often leave you even worse off than before. Not a happy thought.
And that's important to keep in mind because our works, while not the test for in and out, will none the less be tested. We will be held to account for how we stewarded that which God gave us, including our lives, and we will suffer gain or loss accordingly. Some as thru the fires of hell. That's not a happy thought either.
So no, suicide will not keep you out of "heaven", but make no mistake, it won't be a free ride home either.
And again, John 12:25. Most people want to suicide because they hate their lives. God tells us that if we hate our worldly lives because of Him, we're on the right track. And pissing off the enemy by our very presence. That's why satan and his minions don't want us to be present.
Persevere. That's what Jesus says in Revelation, persevere.
In that we will overcome