CANADA STOCKS-TSX records biggest weekly decline since May

* TSX down 115.48 points, or 0.75 percent, at 15,215.26 * Eight of the 10 main index sectors decline * Gold-mining shares climb with bullion price By John Tilak TORONTO, Aug 1 (Reuters) - Canada's main stock index fell on Friday and recorded its biggest weekly decline since early May, rattled by uncertainty about U.S. Federal Reserve's interest-rate stance and by fears that Argentina's debt default might signal broader instability. Global markets have tumbled since the defau