[3.13] gh-132876: workaround broken ldexp() on Windows 10 (GH-133135) (#134685)

* gh-132876: workaround broken ldexp() on Windows 10

ldexp() fails to round subnormal results before Windows 11,
so hide their bug.
(cherry picked from commit cf8941c60356acdd00055e5583a2d64761c34af4)

Co-authored-by: Tim Peters <tim.peters@gmail.com>