Keep two empty lines between declarations for cpp files

src/x64/code-stubs-x64.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 5310 matching lines @@
 
   __ andl(hash, Immediate(String::kHashBitMask));
 
   // if (hash == 0) hash = 27;
   Label hash_not_zero;
   __ j(not_zero, &hash_not_zero);
   __ Set(hash, StringHasher::kZeroHash);
   __ bind(&hash_not_zero);
 }
 
+
 void SubStringStub::Generate(MacroAssembler* masm) {
   Label runtime;
 
   // Stack frame on entry.
   //  rsp[0]  : return address
   //  rsp[8]  : to
   //  rsp[16] : from
   //  rsp[24] : string
 
   const int kToOffset = 1 * kPointerSize;
@@ skipping 1657 matching lines @@
   __ bind(&fast_elements_case);
   GenerateCase(masm, FAST_ELEMENTS);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64