bsc: Reduce TC_bssap_rlsd_does_not_cause_bssmap_reset to 4 lchan

This test establishes an SDCCH for each iteration.  However,
* due to OS#3333, osmo-bsc is currently not properly releasing those
  lchan's,
* due to OS#3222, we furthermore don't allocate "larger" channels like TCH

and as a result on a combined CCCH system we only have 4 SDCCH, which
is less than the 8 that we try to use here.

Change-Id: I0f7fff54248a505387bdfe105259e8ad10ce6c77
Related: OS#3333
Related: OS#3332
diff --git a/bsc/BSC_Tests.ttcn b/bsc/BSC_Tests.ttcn
index 2477539..9c0ec62 100644
--- a/bsc/BSC_Tests.ttcn
+++ b/bsc/BSC_Tests.ttcn
@@ -2046,7 +2046,7 @@
 	/* Setup up a number of connections and RLSD them again from the MSC
 	 * side. In the buggy behavior, the fourth one triggers BSSMAP Reset.
 	 * Let's do it some more times for good measure. */
-	for (i := 0; i < 8; i := i+1) {
+	for (i := 0; i < 4; i := i+1) {
 		/* Since we're doing a lot of runs, give each one a fresh
 		 * T_guard from the top. */
 		T_guard.start;