internal/testprotos: minor .proto file fixes

Add a missing syntax and package statement.

Change-Id: I3c95aa055ad84fa0bbb2bbdd341b51df9359f499
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/217759
Reviewed-by: Joe Tsai <joetsai@google.com>
diff --git a/internal/testprotos/fuzz/fuzz.pb.go b/internal/testprotos/fuzz/fuzz.pb.go
index 21c10c8..64f5b2c 100644
--- a/internal/testprotos/fuzz/fuzz.pb.go
+++ b/internal/testprotos/fuzz/fuzz.pb.go
@@ -1,10 +1,10 @@
-// Code generated by protoc-gen-go. DO NOT EDIT.
-// source: fuzz/fuzz.proto
-
 // Copyright 2019 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Code generated by protoc-gen-go. DO NOT EDIT.
+// source: fuzz/fuzz.proto
+
 package fuzz
 
 import (