MacOS-arm64 native crossgen2 build missing

[sdmaclea]

When building coreclr on Apple Silicon crossgen2 is created for x86_x64 instead of arm64. The native one is missing.

• This is likely blocked on using a .NET 6 preview to build. See Dogfood .NET6 SDK & use native SDK for Apple Silicon native builds (WIP) #47245
• This is likely related to failures in these ready2run tests
  • readytorun/multifolder/multifolder/multifolder.sh
  • readytorun/r2rdump/FrameworkTests/R2RDumpTests/R2RDumpTests.sh
  • readytorun/crossgen2/crossgen2smoke/crossgen2smoke.sh

[mangod9]

cc @AntonLapounov

[sdmaclea]

These tests are disabled for this issue.

runtime/src/tests/issues.targets

Lines 739 to 748 in c320071

	<!-- Crossgen2 issues -->
	<ExcludeList Include="$(XunitTestBinBase)/readytorun/crossgen2/crossgen2smoke/*">
	<Issue>https://github.com/dotnet/runtime/issues/48001</Issue>
	</ExcludeList>
	<ExcludeList Include="$(XunitTestBinBase)/readytorun/multifolder/multifolder/*">
	<Issue>https://github.com/dotnet/runtime/issues/48001</Issue>
	</ExcludeList>
	<ExcludeList Include="$(XunitTestBinBase)/readytorun/r2rdump/FrameworkTests/R2RDumpTests/*">
	<Issue>https://github.com/dotnet/runtime/issues/48001</Issue>
	</ExcludeList>

[mangod9]

Believe this should be fixed.