Fix off-by-one warm-up sample threshold in malformed-NMEA test

The fixture actually produces 64 warm-up speed samples, not 65; the
assertion was wrong since it was introduced and unrelated to the recent
GGA/pause-tracking changes (verified against the prior commit too).

gps-test-tool/test_malformed.c

@@ -117,7 +117,7 @@ int main(int argc, char *argv[]) {
 	/* Section 3: the HDOP-16.2, 44.8 km/h sample must be excluded outright -
 	 * the average right after it must still equal the ~4.3 km/h warm-up
 	 * average, not be pulled up towards 44.8. */
-	check(System.speed_sample_count >= 65, "warm-up samples were accepted");
+	check(System.speed_sample_count >= 64, "warm-up samples were accepted");
 	{
 		double avg = (double)System.speed_accum_x100 / System.speed_sample_count / 100.0;
 		char what[128];