dart2js cps: Clean up and avoid processing unreachable code.

pkg/compiler/lib/src/tree_ir/tree_ir_integrity.dart

 library tree_ir.integrity;
 
 import 'tree_ir_nodes.dart';
 
 /// Performs integrity checks on the tree_ir.
 ///
 /// Should only be run for debugging purposes, not in production.
 ///
 /// - Reference counts on must match the actual number of references.
 /// - Labels must be in scope when referenced.
@@ skipping 111 matching lines @@
   visitContinue(Continue node) {
     if (!label2declaration.containsKey(node.target)) {
       error('Continue to label that is not in scope');
     }
     if (label2declaration[node.target] is! Loop) {
       error('Continue to non-loop statement ${label2declaration[node.target]}');
     }
     labelUses[node.target]++;
   }
 
-  visitInnerFunction(FunctionDefinition node) {
-    checkBody(node);
-  }
-
   void checkBody(FunctionDefinition node) {
     node.parameters.forEach(declare);
     visitStatement(node.body);
     node.parameters.forEach(undeclare);
   }
 
   dynamic error(String message) {
     throw 'Tree IR integrity violation in ${topLevelNode.element}:\n$message';
   }
 
@@ skipping 11 matching lines @@
       if (reads != variable.readCount || writes != variable.writeCount) {
         error('Invalid reference count for $variable:\n'
               '- Variable has $reads reads and $writes writes\n'
               '- Reference count is ${variable.readCount} reads and '
               '${variable.writeCount} writes');
       }
     }
   }
 
 }