Peds: Efforts to find the reason of crashes on GCC 7.5.0

* Prevent deleted peds to be in nearPeds list (was always needed, might be unrelated to crashes)
* Add asserts to nearPeds and PedIK ctor (crash reasons)
* Shouldn't fix reported crashes since they were caused by null peds.

src/peds/PedIK.h

@@ -34,7 +34,7 @@ public:
 		AIMS_WITH_ARM = 4,
 	};
 
-	CPed *m_ped;
+	CPed *Const m_ped;
 	LimbOrientation m_headOrient;
 	LimbOrientation m_torsoOrient;
 	LimbOrientation m_upperArmOrient;