Nikkei sags, heads for first weekly drop in five

* Investors take profits ahead of long weekend * Short-term overheating seen in market * Exporters, Fast Retailing and Toray fall By Thomas Wilson TOKYO, Nov 21(Reuters) - Japanese stocks skidded on Friday as selling ahead of a long weekend and signs of short-term overheating offset a boost from a solid Wall Street performance rooted in U.S economic strength. The Nikkei average shed 0.7 percent to 17,172.82 by 0120 GMT, leaving the benchmark on course to snap a run of four w