Integrate testing for bitop, math and string Lua libraries

- LuaJIT and PUC Rio Lua:
  - [x] https://github.com/ligurio/lua-c-api-tests/pull/124
  - [x] https://github.com/ligurio/lua-c-api-tests/pull/123
  - [x] https://github.com/ligurio/lua-c-api-tests/pull/121