bobzhang/tdfa

This product includes software developed at
International Digital Economy Academy (https://www.idea.edu.cn/).

The following parts are copied or adapted from moonbitlang/core
(https://github.com/moonbitlang/core), licensed under the Apache License,
Version 2.0:

- internal/regex_parser, internal/ast, internal/shared_types,
  internal/rechar_set, internal/symbol_map
- regex.mbt, regex_methods.mbt, regex_pattern.mbt, regex_profile.mbt,
  regex_utf16.mbt and the tests ported with them
