[release/6.0.3xx] [CoreCLR] Avoid having any internal calls in managed code for CoreCLR. Fixes #15343.#15457

rolfbjarne merged 2 commits intodotnet:release/6.0.3xxdotnet/macios:release/6.0.3xxfrom

vs-mobiletools-engineering-service2:backport-pr-15358-to-release/6.0.3xxvs-mobiletools-engineering-service2/xamarin-macios:backport-pr-15358-to-release/6.0.3xxCopy head branch name to clipboard