Cleanup GenFacades logic and don't bind against non-shipping contract assemblies

[ViktorHofer]

Fixes #63467

• Cleanup GenFacades logic and don't bind against non-shipping contract assemblies

Update the GenFacades package and configure it so that shims can pass a different reference assembly in than what they return via the ReferenceAssembly attribute in the AnnotateTargetPathWithTargetPlatformMonikerWithReferenceAssembly target.

Restructure the resolveContract.targets file to make it more shareable with the rest of the repository (potential follow-up change). Define section to better indicate what features the file exposes. Merge the resolveContract.props into it as that file's purpose was limited.

Introduce the AnnotateTargetPathWithContract switch to make it configure-able when a source project should return the reference project's assembly instead of the source assembly, when other projects compile against it. Set it so that reference assemblies are only returned for NetCoreAppCurrent tfms or when the project isn't packable.

• Fix System.DirectoryServices.AccountManagement build

System.DirectoryServices.AccountManagement now builds against
src/System.DirectoryServices instead of ref/System.DirectoryServices
(because the package doesn't contain the ref assembly).

Because of that, the compiler now gets confused because of the
System.DirectoryServices.Interop namespace and the global Interop class.
This happens even though the DirectoryServices.Interop namespace doesn't include any
public types.

That results in the following errors:

src\libraries\System.DirectoryServices.AccountManagement\src\System\DirectoryServices\AccountManagement\AD\SidList.cs(50,26): error CS0246: The type or namespace name 'SID_AND_ATTRIBUTES' could not be found (are you missing a using directive or an assembly reference?)
src\libraries\System.DirectoryServices.AccountManagement\src\System\DirectoryServices\AccountManagement\interopt.cs(439,20): error CS0246: The type or namespace name 'UNICODE_INTPTR_STRING' could not be found (are you missing a using directive or an assembly reference?)

This commit fixes that by removing the System.DirectoryServices.Interop
namespace and moving the types into the parent namespace.

• Suppress nullable warnings in Serialization.Schema

Now that Schema compiles against the source assembly of System.CodeDom,
it receives nullability errors. I'm suppressing them manually for now
but am filing an issue to correctly fix those.

Related: #78036
Opened #78704 to track cleaning-up the introduced nullability suppressions.

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Issue Details

---

Fixes #63467

• Cleanup APICompat and GenAPI logic and don't bind against non-shipping contract assemblies

Update the GenFacades package and configure it so that shims can pass a different reference assembly in than what they return via the ReferenceAssembly attribute in the AnnotateTargetPathWithTargetPlatformMonikerWithReferenceAssembly target.

Restructure the resolveContract.targets file to make it more shareable with the rest of the repository (potential follow-up change). Define section to better indicate what features the file exposes. Merge the resolveContract.props into it as that file's purpose was limited.

Introduce the AnnotateTargetPathWithContract switch to make it configure-able when a source project should return the reference project's assembly instead of the source assembly, when other projects compile against it. Set it so that reference assemblies are only returned for NetCoreAppCurrent tfms or when the project isn't packable.

• Fix System.DirectoryServices.AccountManagement build

System.DirectoryServices.AccountManagement now builds against
src/System.DirectoryServices instead of ref/System.DirectoryServices
(because the package doesn't contain the ref assembly).

Because of that, the compiler now gets confused because of the
System.DirectoryServices.Interop namespace and the global Interop class.
This happens even though the DirectoryServices.Interop namespace doesn't include any
public types.

That results in the following errors:

src\libraries\System.DirectoryServices.AccountManagement\src\System\DirectoryServices\AccountManagement\AD\SidList.cs(50,26): error CS0246: The type or namespace name 'SID_AND_ATTRIBUTES' could not be found (are you missing a using directive or an assembly reference?)
src\libraries\System.DirectoryServices.AccountManagement\src\System\DirectoryServices\AccountManagement\interopt.cs(439,20): error CS0246: The type or namespace name 'UNICODE_INTPTR_STRING' could not be found (are you missing a using directive or an assembly reference?)

This commit fixes that by removing the System.DirectoryServices.Interop
namespace and moving the types into the parent namespace.

• Suppress nullable warnings in Serialization.Schema

Now that Schema compiles against the source assembly of System.CodeDom,
it receives nullability errors. I'm suppressing them manually for now
but am filing an issue to correctly fix those.

Related: #78036

Author:	ViktorHofer
Assignees:	ViktorHofer
Labels:	area-Infrastructure-libraries
Milestone:	-

[akoeplinger]

One question, looks good otherwise.