Goldman Sachs is tapping its upper echelons to navigate a notoriously complicated region where it has stumbled of late: the Middle East.After missing out on at least US$25 billion in deals in Abu Dhabi – the emirate that snubbed the US bank for its involvement in the 1MDB scandal – Goldman Sachs is making a push into Saudi Arabia.Chief executive officer David Solomon – the first chief of a Wall Street bank to visit the kingdom following the murder of government critic Jamal Khashoggi – has…