buffer: define global v8::CFunction objects as const

PR-URL: nodejs#57676
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

Author: mertcanaltin

src/node_buffer.cc

@@ -1525,11 +1525,11 @@ uint32_t FastWriteString(Local<Value> receiver,
       std::min<uint32_t>(dst.length() - offset, max_length));
 }
 
-static v8::CFunction fast_write_string_ascii(
+static const v8::CFunction fast_write_string_ascii(
     v8::CFunction::Make(FastWriteString<ASCII>));
-static v8::CFunction fast_write_string_latin1(
+static const v8::CFunction fast_write_string_latin1(
     v8::CFunction::Make(FastWriteString<LATIN1>));
-static v8::CFunction fast_write_string_utf8(
+static const v8::CFunction fast_write_string_utf8(
     v8::CFunction::Make(FastWriteString<UTF8>));
 
 void Initialize(Local<Object> target,