Baking terrains with GPU PLM results in a system lock-up or crash on Intel MacOS

Steps to reproduce:

1. Download and open LightmapAA.zip project
2. Open TestScene03
3. Make sure that Progressive GPU is selected as the baking backend
4. Click on Generate Lighting

Expected behavior:

• Bake finishes successfully

Actual behavior:

• Entire OS locks up

Notes:

• Reproduces in 2021.3.7f1, 2022.1.11f1, 2022.2.0b3
• Does not reproduce in 2023.1.0a4
• Affects macOS 10.15.7 (19H1922); it does not affect Windows machines
• Reproduced on MBP 2019 using AMD 5500M GPU
• Affects only the GPU lightmapper; CPU lightmapper is not affected
• Reproduces in projects where terrains are GI contributors
• Editor logs contain no stack trace