fix [System.Diagnostics.Process]::GetProcesses(computer) (#25784)

* fix [System.Diagnostics.Process]::GetProcesses(computer)

* Add new test, update condition

* Missed Using declaration

* Catch exceptions

Author: wtgodbe

src/System.Diagnostics.Process/src/System/Diagnostics/PerformanceCounterLib.cs

@@ -205,7 +205,14 @@ internal PerformanceMonitor(string machineName)
             private void Init()
             {
 #if FEATURE_REGISTRY
-                _perfDataKey = Registry.PerformanceData;
+                if (ProcessManager.IsRemoteMachine(_machineName))
+                {
+                    _perfDataKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.PerformanceData, _machineName);
+                }
+                else
+                {
+                    _perfDataKey = Registry.PerformanceData;
+                }
 #endif
             }
 

src/System.Diagnostics.Process/tests/ProcessTests.cs

@@ -4,6 +4,7 @@
 
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.DirectoryServices.ActiveDirectory;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -920,6 +921,30 @@ public void GetProcesses_EmptyMachineName_ThrowsArgumentException()
             AssertExtensions.Throws<ArgumentException>(null, () => Process.GetProcesses(""));
         }
 
+        [Fact]
+        public void GetProcesses_InvalidMachineName_ThrowsInvalidOperationException()
+        {
+            Assert.Throws<InvalidOperationException>(() => Process.GetProcesses(Guid.NewGuid().ToString()));
+        }
+
+        [Fact]
+        public void GetProcesses_RemoteMachinePath_ReturnsExpected()
+        {
+            try
+            {
+                Process[] processes = Process.GetProcesses(Environment.MachineName + "." + Domain.GetComputerDomain());
+                Assert.NotEmpty(processes);
+            }
+            catch (ActiveDirectoryObjectNotFoundException)
+            {
+                //This will be thrown when the executing machine is not domain-joined, i.e. in CI
+            }
+            catch (PlatformNotSupportedException)
+            {
+                //System.DirectoryServices is not supported on all platforms
+            }
+        }
+
         [Fact]
         [SkipOnTargetFramework(TargetFrameworkMonikers.Uap, "Retrieving information about local processes is not supported on uap")]
         public void GetProcessesByName_ProcessName_ReturnsExpected()