Trac #33234: Fix randrange deprecation warning with python-3.10

{{{
.../sage/rings/qqbar.py:2863: DeprecationWarning: non-integer arguments
to randrange() have been deprecated since Python 3.10 and will be
removed in a subsequent version
  roots = p.roots(ring, False)
}}}

URL: https://trac.sagemath.org/33234
Reported by: mjo
Ticket author(s): Michael Orlitzky
Reviewer(s): Frédéric Chapoton

Author: Release Manager

src/sage/rings/polynomial/real_roots.pyx

@@ -409,9 +409,9 @@ cdef class interval_bernstein_polynomial:
         # A different algorithm here might be more efficient.
 
         div = 1024
-        while self.degree() >= div//4:
+        while self.degree() >= (div // 4):
             div = div * 2
-        qdiv = div/4
+        qdiv = div // 4  # divides evenly since div = 1024*2^k
         rand = Integer(ctx.random.randrange(qdiv, 3*qdiv)) / div
         (p1, p2, ok) = self.de_casteljau(ctx, rand)
         ctx.dc_log_append(("div" + self._type_code(), self.scale_log2, self.bitsize, rand, ok, logging_note))