Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

pkg/compiler/lib/src/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 HBaseVisitor implements OptimizationPhase {
   final Map<int, HInstruction> workmap = new Map<int, HInstruction>();
   final List<int> worklist = new List<int>();
   final Map<HInstruction, Function> pendingOptimizations =
@@ skipping 343 matching lines @@
         instruction.block.addBefore(instruction.next, converted);
         receiver.replaceAllUsersDominatedBy(converted.next, converted);
         addDependentInstructionsToWorkList(converted);
       }
     }
 
     return instruction.specializer.computeTypeFromInputTypes(
         instruction, compiler);
   }
 }