BTS_Tests: increate Tguard to 30.0s for TC_rsl_ms_pwr_dyn_up

A comment in f_TC_rsl_ms_pwr_dyn_up() states:

> By default, the MS power loop gets triggered every 4th SACCH block (1.92s).
> We need 9 * 4 dB steps to get from 0 dBm to 33 dBm, so 9 * 1.92s total.
> Add an extra offset to avoid race conditions: +1.92s.

so the alt statement is expected to block for 19.2s, while the guard
timer is set to 20.0s by default.  This is not enough, given that
f_TC_rsl_ms_pwr_dyn_up() also needs to wait for the first SACCH block
before entering the alt statement.

Let's give it more time to run in order to avoid sporadic failures.

Change-Id: Ib7de8383c95ac9e00560f786ec4c56f79f7d81bc
Related: OS#5635
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index a322fde..223e55b 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -3335,7 +3335,7 @@
 	f_init();
 	f_vty_config(BTSVTY, "phy 0", "osmotrx ms-power-loop -10");
 	for (var integer tn := 1; tn <= 1; tn := tn+1) {
-		pars := valueof(t_Pars(t_RslChanNr_Bm(tn), ts_RSL_ChanMode_SIGN));
+		pars := valueof(t_Pars(t_RslChanNr_Bm(tn), ts_RSL_ChanMode_SIGN, t_guard := 30.0));
 		pars.bts0_band := f_vty_get_bts0_band();
 		vc_conn := f_start_handler(refers(f_TC_rsl_ms_pwr_dyn_up), pars, trxc_comp := true);
 		vc_conn.done;