Core/Misc: Fix various crashes, also related to multithreading (#19012)

* When iterating groups we have to either do it not in multithreaded context (map updates) or start with checking maps (they are guaranteed to change in single thread update).
* Properly clear ComboPoint references on player remove 
* remove some possible references item may have when it is deleted during save. 
* Also clear all hostile references when unit is removed from map.

src/server/game/Entities/Unit/Unit.cpp

@@ -8551,12 +8551,12 @@ Unit* Unit::GetNextRandomRaidMemberOrPet(float radius)
         if (Player* Target = itr->GetSource())
         {
             // IsHostileTo check duel and controlled by enemy
-            if (Target != this && Target->IsAlive() && IsWithinDistInMap(Target, radius) && !IsHostileTo(Target))
+            if (Target != this && IsWithinDistInMap(Target, radius) && Target->IsAlive() && !IsHostileTo(Target))
                 nearMembers.push_back(Target);
 
         // Push player's pet to vector
         if (Unit* pet = Target->GetGuardianPet())
-            if (pet != this && pet->IsAlive() && IsWithinDistInMap(pet, radius) && !IsHostileTo(pet))
+            if (pet != this && IsWithinDistInMap(pet, radius) && pet->IsAlive() && !IsHostileTo(pet))
                 nearMembers.push_back(pet);
         }
 
@@ -12245,7 +12245,7 @@ void Unit::CleanupBeforeRemoveFromMap(bool finalCleanup)
     CombatStop();
     ClearComboPointHolders();
     DeleteThreatList();
-    getHostileRefManager().setOnlineOfflineState(false);
+    getHostileRefManager().deleteReferences();
     GetMotionMaster()->Clear(false);                    // remove different non-standard movement generators.
 }
 
@@ -14918,23 +14918,23 @@ void Unit::GetPartyMembers(std::list<Unit*> &TagUnitMap)
             Player* Target = itr->GetSource();
 
             // IsHostileTo check duel and controlled by enemy
-            if (Target && Target->GetSubGroup() == subgroup && !IsHostileTo(Target))
+            if (Target && Target->IsInMap(owner) && Target->GetSubGroup() == subgroup && !IsHostileTo(Target))
             {
-                if (Target->IsAlive() && IsInMap(Target))
+                if (Target->IsAlive())
                     TagUnitMap.push_back(Target);
 
                 if (Guardian* pet = Target->GetGuardianPet())
-                    if (pet->IsAlive() && IsInMap(Target))
+                    if (pet->IsAlive())
                         TagUnitMap.push_back(pet);
             }
         }
     }
     else
     {
-        if (owner->IsAlive() && (owner == this || IsInMap(owner)))
+        if ((owner == this || IsInMap(owner)) && owner->IsAlive())
             TagUnitMap.push_back(owner);
         if (Guardian* pet = owner->GetGuardianPet())
-            if (pet->IsAlive() && (pet == this || IsInMap(pet)))
+            if ((pet == this || IsInMap(pet)) && pet->IsAlive())
                 TagUnitMap.push_back(pet);
     }
 }