Also fix the following:

sage: NF.<a> = QuadraticField(-2)
sage: CIF(a)
...
ValueError: can not convert complex algebraic number to real interval

We also deal with Python 3 compatibility regarding int/long and bytes/unicode.

Depends on #24423

CC: @tscrim

Component: coercion

Author: Jeroen Demeyer

Branch/Commit: 9ac1612

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/24371