src: replace icu with simdutf for char counts

PR-URL: https://github.com/nodejs/node/pull/46472
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

src/inspector/node_string.cc

@@ -1,5 +1,6 @@
 #include "node_string.h"
 #include "node/inspector/protocol/Protocol.h"
+#include "simdutf.h"
 
 #include <unicode/unistr.h>
 
@@ -118,9 +119,8 @@ const uint8_t* CharactersUTF8(const String& s) {
 }
 
 size_t CharacterCount(const String& s) {
-  icu::UnicodeString utf16 =
-      icu::UnicodeString::fromUTF8(icu::StringPiece(s.data(), s.length()));
-  return utf16.countChar32();
+  // TODO(@anonrig): Test to make sure CharacterCount returns correctly.
+  return simdutf::utf32_length_from_utf8(s.data(), s.length());
 }
 
 }  // namespace StringUtil