message: Add TextNormalizer::NormalizeTextToSvs.
  Whole mapping rule from CJK compatibility ideograph to SVS:
  *
diff: @@ -56,6 +56,11 @@ class TextNormalizer {
  return NormalizeTextWithFlag(input, kDefault);
  }
  + // Normalizes Japanese CJK compatibility ideographs to SVS characters.
  + // Returns false and keeps output as is, if no character is normalized.
  + static bool NormalizeTextToSvs(absl::string_view input, std::string *output);
  + static std::string NormalizeTextToSvs(absl::string_view input);
  +
  private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(TextNormalizer);
  };
  