BVH - fix stale current_tree in deactivate function

[lawnjelly]

Fix a bug in deactivate where current_tree variable was stale. This may have resulted in visual anomalies.

Changes passing of current_tree from a member variable to a function argument, making bugs due to stale state less likely.

May fix #48749
May fix #48790

Notes

• Deactivate is only currently used in the render tree, as part of showing and hiding objects.
• This is split from BVH - thread safety option #48892. Originally that PR did two things, the fix here, and also added thread safety. After extensive testing for thread contention neither myself or @pouleyKetchoupp could see it happening, so we can make a separate decision about adding thread safety and it makes sense to separate the PRs. I will change that PR to only include the thread safety.
• I've also changed the name of the variable from current_tree to tree_id, as that name seems to make more sense when passing it as an argument rather than using it as a state.

[pouleyKetchoupp]

Looks good to me. I haven't spotted any problem while testing in render-intensive and physics-intensive projects.

[akien-mga]

Thanks!

[pouleyKetchoupp]

We should also port this PR to master to keep things in sync (although it's used only for physics for now on master so the bug is not present).

[akien-mga]

Cherry-picked for 3.3.3.