bts: Add paging related tests

We're testing at 80% and 200% of PCH capacity, both for either IMSI-only
or TMSI-only paging requests.  The way how we test ensures:

* the expected number of paged mobile identities end up on the Um interface
* we implicitly check the queuing limit of 200 paging records by
  overflowing it in the 20-seconds-of-200%-load cases
* we implicitly check the batching of mobile identities into different
  paging types
* we test the PCH load reporting over RSL

As a side note, in case you were ever wondering what's the expected
paging throughput / capacity, there are now helper functions to compute
it.  For our combined CCCH/SDCCH4, it's about 16 IMSIs per second or
about 32 TMSIs per second.

Change-Id: I0b80b72bdab3d80d915296d70e1174623fbd8610
diff --git a/library/L1CTL_Types.ttcn b/library/L1CTL_Types.ttcn
index f9b4fe8..61d80cf 100644
--- a/library/L1CTL_Types.ttcn
+++ b/library/L1CTL_Types.ttcn
@@ -503,7 +503,8 @@
 
 	/* for matching against incoming DATA_IND */
 	template L1ctlDlMessage t_L1CTL_DATA_IND(template RslChannelNr chan_nr,
-						 template RslLinkId link_id := ?) := {
+						 template RslLinkId link_id := ?,
+						 template octetstring l2_data := ?) := {
 		header := t_L1ctlHeader(L1CTL_DATA_IND),
 		dl_info := {
 			chan_nr := chan_nr,
@@ -516,7 +517,9 @@
 			fire_crc := ?
 		},
 		payload := {
-			data_ind := ?
+			data_ind := {
+				payload := l2_data
+			}
 		}
 	};
 
@@ -538,4 +541,6 @@
 		}
 	};
 
+	const octetstring c_DummyUI := '0303012B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B2B'O;
+
 } with { encode "RAW" };