[NativeAOT-LLVM] Post-merge tasks

[SingleAccretion]

This issue is intended to be a continuously updated list of things that should be done after the next upstream merge or in the merge PR itself (if necessary for a "clean" merge).

Current list:

• Switch NativeAotSupported to true. This shouldn't have the fallout it did last time with Consolidate <NativeAotSupported definitions runtime#103273. (?)
• Add the code from Unhandled exception handler. runtime#109806 to __Finalizer.SingleThreaded.cs.
• Re-enable the disabled DMI tests in HelloWasm after Fix DiagnosticMethodInfo.Create(Delegate) for valuetype methods runtime#110782.

[yowl]

Will we be able to remove Microsoft.DotNet.ILCompiler.SingleEntry.targets, https://github.com/dotnet/runtimelab/pull/2248/files#diff-29f00866a1dc9b2d5c3acb94480513bacbc05775e9ac3dea25215287a20d979aR3 at some point?

[SingleAccretion]

Will we be able to remove Microsoft.DotNet.ILCompiler.SingleEntry.targets at some point?

Not sure. It seems a fine way to share upstream code while pulling runtime pieces from NuGets for now.