Merge pull request containerd#10956 from sondavidb/backport-588b7a1

[release/1.7 backport] testutil: avoid conflict with continuity/testutil

pkg/testutil/helpers.go

@@ -33,7 +33,17 @@ const umountflags int = 0
 var rootEnabled bool
 
 func init() {
-	flag.BoolVar(&rootEnabled, "test.root", false, "enable tests that require root")
+	if flag.Lookup("test.root") == nil {
+		flag.BoolVar(&rootEnabled, "test.root", false, "enable tests that require root")
+	} else {
+		// The flag is already registered by continuity/testutil
+		for _, f := range os.Args {
+			if f == "-test.root" || f == "-test.root=true" {
+				rootEnabled = true
+				break
+			}
+		}
+	}
 }
 
 // DumpDir prints the contents of the directory to the testing logger.