virtio-gpu-gl-device doesn't boot, and virtio-gpu-gl-pci fails after guest reaches gpu

**Describe the issue**
The newly added GL support in 2.2.2 beta is not working properly. `virtio-gpu-gl-device` gets stuck at a black screen before even reaching firmware. `virtio-gpu-gl-pci` runs really slowly, as if each individual GL draw operation is gated by a vsync or flip operation, then eventually errors out when the guest reaches the GPU state. `virtio-ramfb` seems to run as if its "accelerated" GL is actually a softgpu.

**Configuration**
* UTM Version: 2.2.2
* OS Version: macOS Big Sur 11.5.2
* Intel or Apple Silicon? Apple Silicon

**Crash log**
Ah, there is a crash:
[QEMULauncher_2021-09-03-184719_Christophers-Mac-mini.crash.zip](https://github.com/utmapp/UTM/files/7112319/QEMULauncher_2021-09-03-184719_Christophers-Mac-mini.crash.zip)
[QEMULauncher_2021-09-05-134849_Christophers-Mac-mini.crash.zip](https://github.com/utmapp/UTM/files/7112338/QEMULauncher_2021-09-05-134849_Christophers-Mac-mini.crash.zip)

**Debug log**
[missing]

**Upload VM**
Here is the config file for the VM:
[config.plist.zip](https://github.com/utmapp/UTM/files/7112343/config.plist.zip)