gh-140607: Validate returned byte count in RawIOBase.read (#140611)

While `RawIOBase.readinto` should return a count of bytes between 0 and
the length of the given buffer, it is not required to. Add validation
inside RawIOBase.read() that the returned byte count is valid.

Co-authored-by: Shamil <ashm.tech@proton.me>
Co-authored-by: Victor Stinner <vstinner@python.org>