Move i18n-related runtime functions into a separate file.

src/codegen.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_CODEGEN_H_
 #define V8_CODEGEN_H_
 
 #include "src/code-stubs.h"
-#include "src/runtime.h"
+#include "src/runtime/runtime.h"
 
 // Include the declaration of the architecture defined class CodeGenerator.
 // The contract  to the shared code is that the the CodeGenerator is a subclass
 // of Visitor and that the following methods are available publicly:
 //   MakeCode
 //   MakeCodePrologue
 //   MakeCodeEpilogue
 //   masm
 //   frame
 //   script
@@ skipping 152 matching lines @@
 #ifdef DEBUG
 #ifdef V8_TARGET_ARCH_ARM64
   const EmbeddedVector<byte, kNoCodeAgeSequenceLength> old_sequence_;
 #endif
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODEGEN_H_