Revert "Parts must start with 'part of'" and "Attempt to fix VM build"

dart/lib/compiler/implementation/ssa/types_propagation.dart

Index: dart/lib/compiler/implementation/ssa/types_propagation.dart
diff --git a/dart/lib/compiler/implementation/ssa/types_propagation.dart b/dart/lib/compiler/implementation/ssa/types_propagation.dart
index f682d067931696a55f60a40f8121f77caf7c7ffb..377f233b0f402ebabd7926aecf9a3e5ae0250e7c 100644
--- a/dart/lib/compiler/implementation/ssa/types_propagation.dart
+++ b/dart/lib/compiler/implementation/ssa/types_propagation.dart
@@ -2,8 +2,6 @@
 // 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.
 
-part of ssa;
-
 class SsaTypePropagator extends HGraphVisitor implements OptimizationPhase {
 
   final Map<int, HInstruction> workmap;