gh-108494: Build _testclinic_limited on Windows

[vstinner]

Add _testclinic_limited project to the Visual Studio solution:

• In PCbuild/, copy _asyncio.vcxproj to _testclinic_limited.vcxproj,
  replace RootNamespace with "_testclinic_limited".
• In Visual Stuido, open PCbuild\pcbuild.sln, add the existing
  "_testclinic_limited" project to the solution.
• Add a dependency from "python" project to "_testclinic_limited"
  project.
• Save and exit VS.
• Add "_testclinic_limited" to
  in PCbuild\pcbuild.proj.

• Issue: Add support for the limited C API to Argument Clinic #108494

[vstinner]

The _testclinic_limited is now build as expected on Windows. Logs of the Windows x64 GHA CI:

 _testclinic_limited.c Creating library D:\a\cpython\cpython\PCbuild\amd64\_testclinic_limited_d.lib and object D:\a\cpython\cpython\PCbuild\amd64\_testclinic_limited_d.exp _testclinic_limited.vcxproj -> D:\a\cpython\cpython\PCbuild\amd64\_testclinic_limited_d.pyd