[Diagnostics] Enable .NET Runtime crash reporting before signal chaining

[mdh1418]

Android registers signal handlers before .NET's runtime registers its own signal handlers. Android's signal handlers will kill the .NET process before .NET's crash reporting logic has a chance to fire.

In dotnet/runtime#123735, a config property System.Runtime.CrashReportBeforeSignalChaining was added to allow opting-in to switching that order, allowing .NET's crash reporting logic to run.

The config property can possibly be set in

android/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.RuntimeConfig.targets

Line 35 in 5f936b9

<!-- Default RuntimeHostConfigurationOptions -->

and documented here https://github.com/dotnet/android/blob/5f936b91172479056922dd4e49fab98ca0d0443a/Documentation/docs-mobile/building-apps/build-properties.md

After enabling, diagnostics such as logged managed callstacks dotnet/runtime#123824 and a crash report json file written on disk dotnet/runtime#126916 should be available (given the right runtime version)

[jonathanpeppers]

@mdh1418 do we even need a public MSBuild property? Will any customer understand what it does? If not, maybe it can probably be private like $(_AndroidCrashReportBeforeSignalChaining).

[simonrozsival]

I think the question could be posed as: this seems like a good thing, why would anyone want to turn this off? It's all in native code, so there's not even the possibility to save a few kB by trimming the feature away from managed code. If we don't expect people to turn it off, I think we should make it private and only tell developers to disable this feature if it starts causing unexpected problems.