CANADA STOCKS-Ukraine, Gaza conflicts help push TSX off record high

(Adds strategist's comment, details) By Alastair Sharp TORONTO, July 21 (Reuters) - Canada's main stock index retreated on Monday from its record high as a ratcheting-up of fighting in Ukraine and the Israel-Gaza conflict gave investors pause, with energy and mining stocks among the heaviest weights. Clashes broke out in the rebel-held city of Donetsk in eastern Ukraine as investigators sought access to the bodies of the victims of the Malaysian airliner shot down last week. Me