Core/Player: Check Player race and class on login

Don't allow login for Players with bad race/class combination to avoid any further crash later.

src/server/game/Entities/Player/Player.cpp

@@ -17183,6 +17183,14 @@ bool Player::LoadFromDB(uint32 guid, SQLQueryHolder *holder)
     bytes0 |= gender << 16;                                 // gender
     SetUInt32Value(UNIT_FIELD_BYTES_0, bytes0);
 
+    // check if race/class combination is valid
+    PlayerInfo const* info = sObjectMgr->GetPlayerInfo(getRace(), getClass());
+    if (!info)
+    {
+        TC_LOG_ERROR("entities.player", "Player (GUID: %u) has wrong race/class (%u/%u), can't be loaded.", guid, getRace(), getClass());
+        return false;
+    }
+
     SetUInt32Value(UNIT_FIELD_LEVEL, fields[6].GetUInt8());
     SetUInt32Value(PLAYER_XP, fields[7].GetUInt32());