GLOBAL MARKETS-Japanese stocks tumble as yen hovers near 4-week high

* Dollar languishes near 4-week low against yen TOKYO, Jan 14 (Reuters) - Asian shares came under pressure on Tuesday, with Japanese stocks tumbling more than 2 percent as the yen hovered near a four-week high against the dollar after last week's surprisingly weak jobs report raised concerns about the U.S. growth outlook. Tokyo's Nikkei benchmark shed 2.6 percent, hitting a one-month low as ...