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

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

 // Copyright (c) 2012, 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.
 
-part of ssa;
-
 class SsaTypePropagator extends HGraphVisitor implements OptimizationPhase {
 
   final Map<int, HInstruction> workmap;
   final List<int> worklist;
   final Map<HInstruction, Function> pendingOptimizations;
   final HTypeMap types;
 
   final Compiler compiler;
   String get name => 'type propagator';
 
@@ skipping 186 matching lines @@
     // TODO(ngeoffray): Allow speculative optimizations on
     // non-primitive types?
     if (!desiredType.isPrimitive()) return newType;
     return newType.intersection(desiredType);
   }
 
   // Do not use speculative argument type optimization for now.
   void considerForArgumentTypeOptimization(HInstruction instruction) { }
 
 }