Core/Misc: Fix issues reported by static analysis

Coverity defect IDs: 1292769, 1292768, 1292765, 1292763, 1267939

src/server/game/Entities/Object/Object.cpp

@@ -492,6 +492,7 @@ void Object::BuildValuesUpdate(uint8 updateType, ByteBuffer* data, Player* targe
 
     uint32* flags = NULL;
     uint32 visibleFlag = GetUpdateFieldData(target, flags);
+    ASSERT(flags);
 
     for (uint16 index = 0; index < m_valuesCount; ++index)
     {