pcu: f_tc_paging_ps_from_sgsn: move init/shutdown

Prepare to use this shared function in a new test with additional
commands between init, the function and shutdown.

Related: SYS#4878
Change-Id: I6fd523c7f5ab496b3356cf896a8ceaf9b6e874d2
diff --git a/pcu/PCU_Tests.ttcn b/pcu/PCU_Tests.ttcn
index 804644a..f77c4c1 100644
--- a/pcu/PCU_Tests.ttcn
+++ b/pcu/PCU_Tests.ttcn
@@ -3185,9 +3185,6 @@
 	f_init_gprs_ms();
 	ms := g_ms[0]; /* We only use first MS in this test */
 
-	/* Initialize the PCU interface abstraction */
-	f_init_raw(testcasename());
-
 	f_statsd_reset();
 
 	/* Establish BSSGP connection to the PCU */
@@ -3215,20 +3212,33 @@
 		};
 		f_statsd_expect(expect);
 	}
+}
+
+testcase TC_paging_ps_from_sgsn_sign_ptmsi() runs on RAW_PCU_Test_CT {
+	/* Initialize the PCU interface abstraction */
+	f_init_raw(testcasename());
+
+	f_tc_paging_ps_from_sgsn(0, true);
 
 	f_shutdown(__BFILE__, __LINE__, final := true);
 }
 
-testcase TC_paging_ps_from_sgsn_sign_ptmsi() runs on RAW_PCU_Test_CT {
-	f_tc_paging_ps_from_sgsn(0, true);
-}
-
 testcase TC_paging_ps_from_sgsn_sign() runs on RAW_PCU_Test_CT {
+	/* Initialize the PCU interface abstraction */
+	f_init_raw(testcasename());
+
 	f_tc_paging_ps_from_sgsn(0);
+
+	f_shutdown(__BFILE__, __LINE__, final := true);
 }
 
 testcase TC_paging_ps_from_sgsn_ptp() runs on RAW_PCU_Test_CT {
+	/* Initialize the PCU interface abstraction */
+	f_init_raw(testcasename());
+
 	f_tc_paging_ps_from_sgsn(mp_gb_cfg.bvc[0].bvci);
+
+	f_shutdown(__BFILE__, __LINE__, final := true);
 }
 
 /* Verify osmo-pcu handles DL UNIT_DATA from SGSN with IMSI IE correctly. See OS#4729 */