Drop in fps when drawing a spheres at the same position

## Bevy version
0.9, 0.10
## System information
OS: Win 10
AdapterInfo { name: "AMD Radeon(TM) Graphics", vendor: 4098, device: 5686, device_type: IntegratedGpu, driver: "AMD proprietary driver", driver_info: "21.3.1", backend: Vulkan }

## What you did
Created scene with many spheres

## What went wrong
I experiencing a big drop in fps when drawing a N=1000+ of spheres at the same position compared to when they are drawn in different positions (use small random delta vector with magnitude<3f32).
In discord user suggested that quote: "_Looking at trace captures, the same position case shows the prepare set systems all taking a long time and then finishing at about the same time. This means the GPU is busy using the buffers that the prepare systems want to update so they have to wait_"

If it's not clear, break this out into:
-Spheres spawned on startup;
-Tested on Bevy 0.9, 0.10;
-Tested on N range(1000-20000);
-All spheres inside camera view;
-All spheres Visibility::Visible;
-All spheres using PbrBundle;

## Additional information
Other information that can be used to further reproduce or isolate the problem.
**- screenshots**
**- link to discussion**
_https://discord.com/channels/691052431525675048/1083114604391051334_