http: fs_test.go: correct subtle transposition of offset and whence

src/net/http/fs_test.go

@@ -993,7 +993,7 @@ func TestServeContent(t *testing.T) {
 		for _, method := range []string{"GET", "HEAD"} {
 			//restore content in case it is consumed by previous method
 			if content, ok := content.(*strings.Reader); ok {
-				content.Seek(io.SeekStart, 0)
+				content.Seek(0, io.SeekStart)
 			}
 
 			servec <- serveParam{