tree-wide: always use TAKE_FD() when calling rearrange_stdio()

rearrange_stdio() invalidates specified fds even on failure, which means
we should always invalidate the fds we pass in no matter what. Let's
make this explicit by using TAKE_FD() for that everywhere.

Note that in many places we such invalidation doesnt get us much
behaviour-wise, since we don't use the variables anymore later. But
TAKE_FD() in a way is also documentation, it encodes explicitly that the
fds are invalidated here, so I think it's a good thing to always make
this explicit here.

src/shared/exec-util.c

@@ -50,7 +50,7 @@ static int do_spawn(const char *path, char *argv[], int stdout_fd, pid_t *pid, b
                 char *_argv[2];
 
                 if (stdout_fd >= 0) {
-                        r = rearrange_stdio(STDIN_FILENO, stdout_fd, STDERR_FILENO);
+                        r = rearrange_stdio(STDIN_FILENO, TAKE_FD(stdout_fd), STDERR_FILENO);
                         if (r < 0)
                                 _exit(EXIT_FAILURE);
                 }