Verify if the adapter is available in RenderingContextDriverD3D12::_initialize_devices

[scgm0]

Fix #112282

According to Microsoft's documentation, when the ppDevice parameter of D3D12CreateDevice is null, it can verify whether a device can be created without actually creating one. Therefore, it should be possible to use this method to determine if an adapter is truly available.

Although I'm not entirely sure if my code is correct, I have conducted simple tests on both a Windows 11 virtual machine and a physical machine. Now, it correctly triggers rendering fallback in the virtual machine, and the physical machine can also use d3d12 normally.

It's still uncertain what impact this has on performance.

[blueskythlikesclouds]

Code make sense to me, but the device initialization process warrants a refactor to fix #98207 anyway, which would also naturally handle your issue. It's better if we can avoid the D3D12 runtime validating the adapter twice.

[scgm0]

Code make sense to me, but the device initialization process warrants a refactor to fix #98207 anyway, which would also naturally handle your issue. It's better if we can avoid the D3D12 runtime validating the adapter twice.

It appears that some functionalities can only be verified after the device is created. The solutions are either to move the actual logic of device initialization to RenderingContextDriverD3D12 for verification, or to add minimal device initialization code in RenderingContextDriverD3D12 for validation purposes.

So, should I close this PR and wait for the refactoring, or can we merge this PR first and then proceed with the refactoring?