[string] Move String.p.toLowerCase to CSA

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index bac0a862d1ca92329a1b763b50faa27543149c20..7be1394dbd431b58cc5f29f34bb72a2ae9a3df92 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -993,6 +993,11 @@ class ExternalReference BASE_EMBEDDED {
 
   static ExternalReference try_internalize_string_function(Isolate* isolate);
 
+#ifdef V8_INTL_SUPPORT
+  static ExternalReference intl_convert_one_byte_to_lower(Isolate* isolate);
+  static ExternalReference intl_to_latin1_lower_table(Isolate* isolate);
+#endif  // V8_INTL_SUPPORT
+
   template <typename SubjectChar, typename PatternChar>
   static ExternalReference search_string_raw(Isolate* isolate);