cmd/go/internal/lockedfile: skip flaky TestTransform on plan9

Updates #35471

Change-Id: Ie06c442e405a267eb909621e1205444b6a00fda1
Reviewed-on: https://go-review.googlesource.com/c/go/+/206197
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David du Colombier <0intro@gmail.com>

src/cmd/go/internal/lockedfile/transform_test.go

@@ -10,8 +10,10 @@ package lockedfile_test
 import (
 	"bytes"
 	"encoding/binary"
+	"internal/testenv"
 	"math/rand"
 	"path/filepath"
+	"runtime"
 	"testing"
 	"time"
 
@@ -35,6 +37,10 @@ func roundDownToPowerOf2(x int) int {
 }
 
 func TestTransform(t *testing.T) {
+	if runtime.GOOS == "plan9" {
+		testenv.SkipFlaky(t, 35471)
+	}
+
 	dir, remove := mustTempDir(t)
 	defer remove()
 	path := filepath.Join(dir, "blob.bin")