tst-tzset: raise timeout to 5 seconds

This test is reliably taking 2.3 seconds on my system, and the default
is 2 seconds, so it always times out.  Bump it up to 5 seconds instead.

timezone/tst-tzset.c

@@ -25,6 +25,7 @@
 #include <time.h>
 #include <unistd.h>
 
+#define TIMEOUT 5
 static int do_test (void);
 #define TEST_FUNCTION do_test ()
 #include "../test-skeleton.c"