Make sure both stdout and stderr can be redirected from a native executable (#20997)

test/powershell/Language/Scripting/NativeExecution/NativeCommandProcessor.Tests.ps1

@@ -213,6 +213,12 @@ Describe "Native Command Processor" -tags "Feature" {
         Wait-UntilTrue -sb { (Get-Process mmc).Count -gt 0 } -TimeoutInMilliseconds 5000 -IntervalInMilliseconds 1000 | Should -BeTrue
         Get-Process mmc | Stop-Process
     }
+
+    It 'Can redirect stdout and stderr to different files' {
+        testexe -stderrandout testing > $TestDrive/stdout.txt 2> $TestDrive/stderr.txt
+        Get-Content $TestDrive/stdout.txt | Should -Be testing
+        Get-Content $TestDrive/stderr.txt | Should -Be gnitset
+    }
 }
 
 Describe "Open a text file with NativeCommandProcessor" -tags @("Feature", "RequireAdminOnWindows") {