flow: make exc policy work w/ simulated flowmemcap

Exception policy wouldn't be applied if we were in the context of a
simulated flow memcap hit.

Bug #5998

(cherry picked from commit 1665f71a68)

src/flow-hash.c

@@ -541,6 +541,8 @@ static Flow *FlowGetNew(ThreadVars *tv, FlowLookupStruct *fls, Packet *p)
     const bool emerg = ((SC_ATOMIC_GET(flow_flags) & FLOW_EMERGENCY) != 0);
 #ifdef DEBUG
     if (g_eps_flow_memcap != UINT64_MAX && g_eps_flow_memcap == p->pcap_cnt) {
+        NoFlowHandleIPS(p);
+        StatsIncr(tv, fls->dtv->counter_flow_memcap);
         return NULL;
     }
 #endif