tests/attach-f-p.c: increase timeouts

Increase timeouts to make the test more reliable on slow systems.

* tests/attach-f-p.c (its): Increase timeouts to 1, 2, and 3 seconds,
respectively.
diff --git a/tests/attach-f-p.c b/tests/attach-f-p.c
index 51a5333..c0d4960 100644
--- a/tests/attach-f-p.c
+++ b/tests/attach-f-p.c
@@ -58,9 +58,9 @@
 };
 static const int sigs[N] = { SIGALRM, SIGUSR1, SIGUSR2 };
 static const struct itimerspec its[N] = {
-	{ .it_value.tv_nsec = 500000000 },
-	{ .it_value.tv_nsec = 700000000 },
-	{ .it_value.tv_nsec = 900000000 },
+	{ .it_value.tv_sec = 1 },
+	{ .it_value.tv_sec = 2 },
+	{ .it_value.tv_sec = 3 }
 };
 static thread_arg_t args[N] = {
 	{ .no = 0 },