[iOS/tvOS] System.Diagnostics.Tests.ProcessTests.TestGetProcesses fails on devices

[steveisok]

This test fails with:

System.ComponentModel.Win32Exception : Could not get all running Process IDs.

Stack trace
   at Interop.libproc.proc_listallpids()
   at System.Diagnostics.ProcessManager.GetProcessInfos(String machineName)
   at System.Diagnostics.Process.GetProcesses(String machineName)
   at System.Diagnostics.Process.GetProcesses()
   at System.Diagnostics.Tests.ProcessTests.TestGetProcesses()
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)

I suspect we'll need to bring in the headers for proc_listallpids

[MaximLipnin]

It might be addressed when #61265 (comment) is done.

[akoeplinger]

This and the other tests disabled against #60588 on iOS/tvOS can be skipped with SkipOnPlatform since these APIs throw PNSE now.

[MaximLipnin]

This and the other tests disabled against #60588 on iOS/tvOS can be skipped with SkipOnPlatform since these APIs throw PNSE now.

Addressed in #61670