Keep two empty lines between declarations for cpp files

src/hydrogen-instructions.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1683 matching lines @@
   switch (check_) {
     case IS_SPEC_OBJECT: return "object";
     case IS_JS_ARRAY: return "array";
     case IS_STRING: return "string";
     case IS_INTERNALIZED_STRING: return "internalized_string";
   }
   UNREACHABLE();
   return "";
 }
 
+
 void HCheckInstanceType::PrintDataTo(StringStream* stream) {
   stream->Add("%s ", GetCheckName());
   HUnaryOperation::PrintDataTo(stream);
 }
 
 
 void HCheckPrototypeMaps::PrintDataTo(StringStream* stream) {
   stream->Add("[receiver_prototype=%p,holder=%p]%s",
               *prototypes_.first(), *prototypes_.last(),
               CanOmitPrototypeChecks() ? " (omitted)" : "");
@@ skipping 2172 matching lines @@
     case kBackingStore:
       if (!name_.is_null()) stream->Add(*String::cast(*name_)->ToCString());
       stream->Add("[backing-store]");
       break;
   }
 
   stream->Add("@%d", offset());
 }
 
 } }  // namespace v8::internal