Revert "Simplify and fix implicit closure check, speed up Closure_equals"

runtime/vm/source_report.cc

 // Copyright (c) 2015, 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.
 #ifndef PRODUCT
 #include "vm/source_report.h"
 
 #include "vm/compiler.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
@@ skipping 64 matching lines @@
         ((end_pos_ > TokenPosition::kMinSource) &&
          (func.token_pos() > end_pos_))) {
       // The function does not intersect with the requested token range.
       return true;
     }
   }
 
   switch (func.kind()) {
     case RawFunction::kRegularFunction:
     case RawFunction::kClosureFunction:
-    case RawFunction::kImplicitClosureFunction:
     case RawFunction::kGetterFunction:
     case RawFunction::kSetterFunction:
     case RawFunction::kConstructor:
       break;
     default:
       return true;
   }
   if (func.is_abstract() || func.IsImplicitConstructor() ||
       func.IsRedirectingFactory()) {
     return true;
@@ skipping 415 matching lines @@
     VisitClosures(&ranges);
   }
 
   // Print the script table.
   JSONArray scripts(&report, "scripts");
   PrintScriptTable(&scripts);
 }
 
 }  // namespace dart
 #endif  // PRODUCT