dart2js cps: Clean up and avoid processing unreachable code.

pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart

Index: pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
diff --git a/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart b/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
index 14069e87ac0e6a9b3bebc134b43a49bbf0ab14c2..2f5a9fd870735b49b6173584b856694908f60011 100644
--- a/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
+++ b/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
@@ -52,13 +52,13 @@ import '../tree_ir_nodes.dart';
 ///
 /// Note that the pattern above needs no iteration since nested ifs have been
 /// collapsed previously in the [StatementRewriter] phase.
-/// 
+///
 ///
 /// PULL INTO UPDATE EXPRESSION:
-/// 
+///
 /// Assignment expressions before the unique continue to a [whileCondition] are
 /// pulled into the updates for the loop.
-/// 
+///
 ///   L:
 ///   for (; condition; updates) {
 ///     S [ x = E; continue L ]
@@ -69,7 +69,7 @@ import '../tree_ir_nodes.dart';
 ///     S [ continue L ]
 ///   }
 ///
-/// The decision to only pull in assignments is a heuristic to balance 
+/// The decision to only pull in assignments is a heuristic to balance
 /// readability and stack trace usability versus the modest code size
 /// reduction one might get by aggressively moving expressions into the
 /// updates.
@@ -88,11 +88,6 @@ class LoopRewriter extends RecursiveTransformer
     root.body = visitStatement(root.body);
   }
 
-  @override
-  void visitInnerFunction(FunctionDefinition node) {
-    node.body = new LoopRewriter().visitStatement(node.body);
-  }
-
   Statement visitContinue(Continue node) {
     usedContinueLabels.add(node.target);
     return node;