[string] Move String.p.toLowerCase to CSA

src/intl.h

Index: src/intl.h
diff --git a/src/intl.h b/src/intl.h
index 529ae03d4de40dae9f46b36f520c4467da3d339e..90683fe7f60fffe8811e63b6dd5898881ea149e6 100644
--- a/src/intl.h
+++ b/src/intl.h
@@ -30,6 +30,11 @@ MUST_USE_RESULT Object* ConvertToUpper(Handle<String> s, Isolate* isolate);
 MUST_USE_RESULT Object* ConvertCase(Handle<String> s, bool is_upper,
                                     Isolate* isolate);
 
+MUST_USE_RESULT Object* ConvertOneByteToLower(String* src, String* dst,
+                                              Isolate* isolate);
+
+const uint8_t* ToLatin1LowerTable();
+
 // ICUTimezoneCache calls out to ICU for TimezoneCache
 // functionality in a straightforward way.
 class ICUTimezoneCache : public base::TimezoneCache {