By Damian J. Troise NEW YORK (AP) — Trade war turmoil is weighing heavily on financial markets in Canada. Canada’s main stock index has been tumbling along with U.S. indexes since President Donald Trump initiated a trade war with his North American neighbors. Mexico’s main stock index has remained relatively steady following measures from the Mexican government to stabilize financial markets. The Toronto Stock Exchange’s S&P/TSX composite index reached an all-time high on Jan. 30. It started sliding a day later following the first salvo in the form of announced 25% tariffs on all goods from Canada and Mexico. Since then, Trump has rattled markets with uncertainty as he changes his mind on implementing or delaying tariffs on a seemingly daily basis. The S&P/TSX composite has shed about 5% since…