Repro steps:
1. On OSX, Open Unity 2019.3.0a12 or later.
2. Import the VFX Graph package (7.0.1 or later)
3. Create a default VFX asset
4. Drag the asset in the hierarchy or scene (make sure either the scene or game view is visible)
5. If nothing happens, open the asset in the VFX Window so it would compile.
6. Mac hangs, then crashes and restarts.

Reproducible with: 2019.3.0a11, 2019.3.0b1, 2020.1.0a1
Not reproducible with: 2019.3.0a10 and lower

Mac crash at:
com.apple.CoreDisplay 0x00007fff3c1c2e38 CoreDisplay::GPU::GPU(__GPUWranglerGPU*, dispatch_queue_s*) + 792
8 com.apple.CoreDisplay 0x00007fff3c1d7dc5 invocation function for block

Notes:
- discovered during 7.0.1 validation, was presumed to be a temporary trunk issue, still repros 2 weeks later, so logging it.
- repros on HDRP, Universal, or when no SRP is assigned.