fix msc_vlr tests after libosmocore uses localtime for SMS

libosmocore change-id I4efdb1eaae43aced33961b64d4f14b0040321c10 changes the
gsm340_gen_scts() from gmtime to localtime, meaning that by feeding a mere zero
as timestamp, we get different results depending on the local machine's
timezone setting. Instead of calling gsm340_gen_scts() with zero, simply write
a bunch of bytes as time so that the tests get identical SMS bytes every time.

Change-Id: I8a50e8963dce80609749571b61fc6ffe1c54660c

tests/msc_vlr/msc_vlr_tests.c

@@ -242,8 +242,8 @@ int __wrap_RAND_bytes(unsigned char *buf, int num)
 void __real_gsm340_gen_scts(uint8_t *scts, time_t time);
 void __wrap_gsm340_gen_scts(uint8_t *scts, time_t time)
 {
-	/* Remove the time to encode for deterministic test results */
-	__real_gsm340_gen_scts(scts, 0);
+	/* Write fixed time bytes for deterministic test results */
+	osmo_hexparse("07101000000000", scts, 7);
 }
 
 const char *paging_expecting_imsi = NULL;