Improve AStarGrid2D performance when jumping is enabled

[10Drenth]

fixes #91367

On sparse grids, enabling jumping can now increase performance 5x, which should be more than 10x faster than before, as jumping unintentionally used to decrease performance instead.

AStarGrid_jumping_Performance.zip

[Chaosus]

I see some inconsistencies with current pathfinding:

At this commit:

At master:

You can check it up using https://github.com/theshaggydev/the-shaggy-dev-projects/tree/main/projects/godot-4/astargrid2d

[Chaosus]

I think it's a correct now, great, thanks.

[akien-mga]

I notice this PR and #85965 (both ready to merge) will conflict, so one would need to be merged first and the other rebased. But I wanted to take the opportunity to get both checked in parallel, I'm not familiar with AStar implementation but I wonder if there's overlap in what those two optimizations aim to solve, and thus whether they will combine well or not.

CC @ershn @godotengine/navigation

[10Drenth]

I wonder if there's overlap in what those two optimizations aim to solve

I'd say they do exist in separate spaces, but I'd have to check whether this specific optimization is still significantly faster compared to improved general performance from the other PR

[10Drenth]

On a second look, the linked PR appears to be completely separate. I am also not seeing any conflicts with their changes

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉