ci: run plugin tests on Windows (#8314)

Plugin package tests previously ran only on Linux, so Windows-
specific failures were never caught. Run them in CI and make the
affected tests portable across platforms.

Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>

plugin/file/tree/print_test.go

@@ -72,11 +72,16 @@ func TestPrint(t *testing.T) {
 
 	f, err := os.CreateTemp(t.TempDir(), "print_test_tmp")
 	if err != nil {
-		t.Error(err)
+		t.Fatal(err)
 	}
-	defer os.Remove(f.Name())
-	//Redirect the printed results to a tmp file for later comparison
+	// Redirect Print output to a temp file, then restore stdout and close
+	// the handle so TempDir cleanup can remove it on Windows.
+	stdout := os.Stdout
 	os.Stdout = f
+	t.Cleanup(func() {
+		os.Stdout = stdout
+		f.Close()
+	})
 
 	tree.Print()
 	/**
@@ -85,12 +90,12 @@ func TestPrint(t *testing.T) {
 	  server3.example.com.
 	*/
 
+	if _, err := f.Seek(0, 0); err != nil {
+		t.Fatal(err)
+	}
 	buf := make([]byte, 256)
-	f.Seek(0, 0)
-	_, err = f.Read(buf)
-	if err != nil {
-		f.Close()
-		t.Error(err)
+	if _, err := f.Read(buf); err != nil {
+		t.Fatal(err)
 	}
 	height := strings.Count(string(buf), ". \n")
 	//Compare the height of the print with the actual height of the tree