Enable host.pkg subset in source-build

[MichaelSimons]

Related to dotnet/source-build#2421

microsoft.netcore.dotnethostresolver and microsoft.netcore.dotnetapphost are missing from source-build which is introducing prebuilts. This is a regression from 5.0 introduced by the ArPow source-build restructuring.

[ghost]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[ghost]

Tagging subscribers to this area: @dotnet/runtime-infrastructure
See info in area-owners.md if you want to be subscribed.

Issue Details

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Related to dotnet/source-build#2421

microsoft.netcore.dotnethostresolver and microsoft.netcore.dotnetapphost are missing from source-build which is introducing prebuilts. This is a regression from 5.0 introduced by the ArPow source-build restructuring.

Author:	MichaelSimons
Assignees:	ViktorHofer, crummel
Labels:	area-Infrastructure
Milestone:	-

[MichaelSimons]

@ViktorHofer - Build MacCatalyst x64 Release AllSubsets_Mono tests keep timing out. Seems unrelated to these changes.

[ViktorHofer]

Yes that's unrelated and tracked via #58549