Subzero: Do class definition cleanups for assembler files too.

Similar to https://codereview.chromium.org/656123003/, but cover some of
the assembler files which were avoided to avoid conflicts.

BUG=none
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/643903006
diff --git a/src/IceMemoryRegion.cpp b/src/IceMemoryRegion.cpp
index 9c42940..ccfd3cf 100644
--- a/src/IceMemoryRegion.cpp
+++ b/src/IceMemoryRegion.cpp
@@ -1,10 +1,11 @@
+//===- subzero/src/IceMemoryRegion.cpp - Memory region --------------------===//
 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Modified by the Subzero authors.
 //
-//===- subzero/src/IceMemoryRegion.cpp - Memory region --------------------===//
+//===----------------------------------------------------------------------===//
 //
 //                        The Subzero Code Generator
 //