bpo-31806: Use _PyTime_ROUND_TIMEOUT for the timeout argument parsing in more functions (#4026)

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.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 5df9d01..0758f9b 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -2539,7 +2539,7 @@
     }
 
     if (_PyTime_FromSecondsObject(timeout,
-                                  timeout_obj, _PyTime_ROUND_CEILING) < 0)
+                                  timeout_obj, _PyTime_ROUND_TIMEOUT) < 0)
         return -1;
 
     if (*timeout < 0) {
@@ -2548,10 +2548,10 @@
     }
 
 #ifdef MS_WINDOWS
-    overflow |= (_PyTime_AsTimeval(*timeout, &tv, _PyTime_ROUND_CEILING) < 0);
+    overflow |= (_PyTime_AsTimeval(*timeout, &tv, _PyTime_ROUND_TIMEOUT) < 0);
 #endif
 #ifndef HAVE_POLL
-    ms = _PyTime_AsMilliseconds(*timeout, _PyTime_ROUND_CEILING);
+    ms = _PyTime_AsMilliseconds(*timeout, _PyTime_ROUND_TIMEOUT);
     overflow |= (ms > INT_MAX);
 #endif
     if (overflow) {