[3.6] bpo-31806: Use _PyTime_ROUND_TIMEOUT for the timeout argument parsing in more...

[3.6] bpo-31806: Use _PyTime_ROUND_TIMEOUT for the timeout argument parsing in more functions (GH-4026) (#4032)

Fix timeout rounding in time.sleep(), threading.Lock.acquire() and
socket.socket.settimeout() to round correctly negative timeouts between -1.0 and
0.0. The functions now block waiting for events as expected. Previously, the
call was incorrectly non-blocking.
(cherry picked from commit 59af94fa61bf90adbe624508e909b5d6ef6e8464)