Mexico’s great distance runner, Juan Luis Barrios, will race the 2019 Scotiabank Toronto Waterfront Marathon on October 20, he and it race director Alan Brookes announced in Mexico City last month. Barrios has fond memories of Toronto, where he won the gold medal in the 5,000m at the 2015 Pan Am Games. RELATED: Coolsaet, Watson and Wykes to race Canadian Marathon Championships at STWM 2019 Barrios was scheduled to represent Mexico at the Pan Am Games in Lima, Peru this month,…