When running the DllImportGenerator.Tests test suite against CoreCLR x86 Checked builds, sometimes we get an assert failure when calling GC.Collect in an UnmanagedCallersOnly method that was called from managed code with some native code in between.

See https://dev.azure.com/dnceng/public/_build/results?buildId=1429326&view=ms.vss-test-web.build-test-results-tab&runId=41318808&resultId=188820&paneView=debug for a repro in a rolling build.

This took about 40-50 runs locally to reproduce, so it's a rare occurrence.

After some basic investigation, it looks like the CrawlFrame instance has a null ControlPC, so something is not being constructed/discovered correctly with it.