Entities/Unit: Adjust an overzealous assert to not catch self references, and add the inverse assert too. 396f87c follow-up.

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

@@ -412,7 +412,8 @@ Unit::~Unit()
     ASSERT(m_removedAuras.empty());
     ASSERT(m_gameObj.empty());
     ASSERT(m_dynObj.empty());
-    ASSERT(!m_playerMovingMe);
+    ASSERT(!m_unitMovedByMe || (m_unitMovedByMe == this));
+    ASSERT(!m_playerMovingMe || (m_playerMovingMe == this));
 }
 
 void Unit::Update(uint32 p_time)