LibUnicode: Sort special casing array by locale specificity

This is to simply the Default Case Conversion implementation. Otherwise,
the implementation would need to determine which special casing rule to
apply, instead of just picking the first match.

Meta/Lagom/Tools/CodeGenerators/LibUnicode/GenerateUnicodeData.cpp

@@ -181,7 +181,6 @@ static void parse_special_casing(Core::File& file, UnicodeData& unicode_data)
         VERIFY(segments.size() == 5 || segments.size() == 6);
 
         SpecialCasing casing {};
-        casing.index = static_cast<u32>(unicode_data.special_casing.size());
         casing.code_point = AK::StringUtils::convert_to_uint_from_hex<u32>(segments[0]).value();
         casing.lowercase_mapping = parse_code_point_list(segments[1]);
         casing.titlecase_mapping = parse_code_point_list(segments[2]);
@@ -214,6 +213,19 @@ static void parse_special_casing(Core::File& file, UnicodeData& unicode_data)
 
         unicode_data.special_casing.append(move(casing));
     }
+
+    quick_sort(unicode_data.special_casing, [](auto const& lhs, auto const& rhs) {
+        if (lhs.code_point != rhs.code_point)
+            return lhs.code_point < rhs.code_point;
+        if (lhs.locale.is_empty() && !rhs.locale.is_empty())
+            return false;
+        if (!lhs.locale.is_empty() && rhs.locale.is_empty())
+            return true;
+        return lhs.locale < rhs.locale;
+    });
+
+    for (u32 i = 0; i < unicode_data.special_casing.size(); ++i)
+        unicode_data.special_casing[i].index = i;
 }
 
 static void parse_prop_list(Core::File& file, PropList& prop_list, bool multi_value_property = false)