BUG: read_json not reading in large ints properly 
- [x] closes #20608
- [x] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [x] whatsnew entry

Casting to int64 / float64 is unfortunately not going to work generically here. I think @arw2019 was closer to a solution in #34984 - maybe something you can pick up? OK, closing then. Python C API stuff is a little bit over my head. 