use append

R=gri, r, r2
CC=golang-dev
https://golang.org/cl/2743042
diff --git a/src/pkg/os/file_windows.go b/src/pkg/os/file_windows.go
index f13911a..bf710bb 100644
--- a/src/pkg/os/file_windows.go
+++ b/src/pkg/os/file_windows.go
@@ -157,13 +157,7 @@
 			continue
 		}
 		count--
-		if len(fi) == cap(fi) {
-			nfi := make([]FileInfo, len(fi), 2*len(fi))
-			copy(nfi, fi)
-			fi = nfi
-		}
-		fi = fi[0 : len(fi)+1]
-		fi[len(fi)-1] = f
+		fi = append(fi, f)
 	}
 	return fi, nil
 }