BUG: Refactor complex floor_divide to avoid osx-arm64 opt warnings - #17712

___________________ TestDivision.test_floor_division_complex ___________________

self = <numpy.core.tests.test_umath.TestDivision object at 0x7fda6e16e090>

    def test_floor_division_complex(self):
        # check that implementation is correct
        msg = "Complex floor division implementation check"
        x = np.array([.9 + 1j, -.1 + 1j, .9 + .5*1j, .9 + 2.*1j], dtype=np.complex128)
        y = np.array([0., -1., 0., 0.], dtype=np.complex128)
        assert_equal(np.floor_divide(x**2, x), y, err_msg=msg)
        # check overflow, underflow
        msg = "Complex floor division overflow/underflow check"
        x = np.array([1.e+110, 1.e-110], dtype=np.complex128)
>       y = np.floor_divide(x**2, x)
E       RuntimeWarning: overflow encountered in floor_divide

msg        = 'Complex floor division overflow/underflow check'
self       = <numpy.core.tests.test_umath.TestDivision object at 0x7fda6e16e090>
x          = array([1.e+110+0.j, 1.e-110+0.j])
y          = array([ 0.+0.j, -1.+0.j,  0.+0.j,  0.+0.j])