Core/Movement: Add LOS check for fleeingmovement target point.

Prevents fleeing or feared units from going to upper floor ignoring walls/ceilings with mmaps on(and usually get stucked).

Current implementation just randomly selects a distance and angle against the frighting unit, when in narrow circumstance such as underground caves, such targeting point would be at another floor.

Closes #11300
Ref #9475 (needs fixed confirmation)

src/server/scripts/Pet/pet_dk.cpp

@@ -54,7 +54,7 @@ class npc_pet_dk_ebon_gargoyle : public CreatureScript
                 uint64 ownerGuid = me->GetOwnerGUID();
                 if (!ownerGuid)
                     return;
-                
+
                 // Find victim of Summon Gargoyle spell
                 std::list<Unit*> targets;
                 Trinity::AnyUnfriendlyUnitInObjectRangeCheck u_check(me, me, 30.0f);