Kill only if not exited yet

Author: Youssef1313

test/Utilities/Microsoft.Testing.TestInfrastructure/CommandLine.cs

@@ -86,5 +86,11 @@ private static string ClearBOM(string outputLine)
         return firstChar == byteOrderMark ? outputLine[1..] : outputLine;
     }
 
-    public void Dispose() => _process?.Kill();
+    public void Dispose()
+    {
+        if (_process?.HasExited == false)
+        {
+            _process.Kill();
+        }
+    }
 }

test/Utilities/Microsoft.Testing.TestInfrastructure/IProcessHandle.cs

@@ -15,6 +15,8 @@ public interface IProcessHandle
 
     TextReader StandardOutput { get; }
 
+    bool HasExited { get; }
+
     void Dispose();
 
     void Kill();

test/Utilities/Microsoft.Testing.TestInfrastructure/ProcessHandle.cs

@@ -24,6 +24,8 @@ internal ProcessHandle(Process process, ProcessHandleInfo processHandleInfo)
 
     public TextReader StandardOutput => _process.StandardOutput;
 
+    public bool HasExited => _process.HasExited;
+
     public int ExitCode => _process.ExitCode;
 
     public async Task<int> WaitForExitAsync(CancellationToken cancellationToken = default)