[RESTRICT AUTOMERGE] Fix ioutil import in sc-dev branch

Looks like the change from rvc-dev (https://googleplex-android-review.git.corp.google.com/c/platform/build/soong/+/18971604),
when merged into sc-dev removes the ioutil import which is actually
being used.

Test: Ran a build and made sure Soong bootstrap works.

Bug: b/236642556
Change-Id: I2b85b7f4787ec2df5082ebfc969887495763aa3b
(cherry picked from commit 4a31fb1004)

cmd/soong_ui/main.go

@@ -18,6 +18,7 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"