CALayer APIs handling CGColorRef can crash due to GC timing

[Therzok]

Steps to Reproduce

1. See the discussion here https://github.com/xamarin/Xamarin.PropertyEditing/pull/821#discussion_r927049949
2. CALayer's APIs that use CGColor should be used in high allocation rate conditions (i.e. backgroundColor)
3. Create a lot of them, set them.

Expected Behavior

No crash

Actual Behavior

The native API might CFRetain the CGColorRef way too late, and dotnet precise GC scanning will mark it eligible for collection as soon as the PInvoke interop boundary is crossed.

Environment

Version information

dotnet workload list

macos                       SDK 6.0.300

[chamons]

FYI @rolfbjarne maybe we should look at this when you or both of us get back?

[rolfbjarne]

This seems to be a variation of #10146.