fix: avoid unnecessary window.makeCurrent() calls

[McMurat]

This fixes the issue as discussed here

[tommyettinger]

I'm just commenting to try to bring some eyes to this; I don't personally feel like I can adequately review the code for correctness. I can review it for performance in a little while. I've had my suspicions about LWJGL3 not running as fast as it could for a while, but it's hard to compare different versions for speed. GL30 is much slower than GL20 on my machine, when using LWJGL3, which is odd, but I'm not sure if that's related to this.

[casid]

I tried this patch with my game on windows and on mac.

It worked on both and subjectively the game felt a little smoother than before.

I have vsync activated and I'm profiling how long rendering the scene takes. Before the patch, on windows the rendering took a few us, now it takes roughly 16ms. Seems like this change made vsync work properly. On mac on the other hand no changes after the patch, rendering is still a few us.