sws: close sockets properly

Fix a bug where closed sockets (fd -1) were left in the all_sockets
list, because of missing parens in a pointer arithmetic expression

Reenable the tests that were locking up due to this bug.

tests/data/DISABLED

@@ -5,6 +5,3 @@
 594
 1209
 1211
-2025
-2028
-2031

tests/server/sws.c

@@ -2065,9 +2065,9 @@ int main(int argc, char *argv[])
     /* Clear out closed sockets */
     for (socket_idx = num_sockets - 1; socket_idx >= 1; --socket_idx) {
       if (CURL_SOCKET_BAD == all_sockets[socket_idx]) {
-        char* dst = (char *) all_sockets + socket_idx;
-        char* src = (char *) all_sockets + socket_idx + 1;
-        char* end = (char *) all_sockets + num_sockets;
+        char* dst = (char *) (all_sockets + socket_idx);
+        char* src = (char *) (all_sockets + socket_idx + 1);
+        char* end = (char *) (all_sockets + num_sockets);
         memmove(dst, src, end - src);
         num_sockets -= 1;
       }