By Neil Jerome Morales and Lisa Marie David MANILA (Reuters) -Crowds of hundreds of thousands massed in the Philippines on Saturday where the leading presidential candidates made a last-ditch bid to sway undecided voters with patriotic, upbeat messages after a divisive election race. Fireworks lit up the sky as singers, celebrities and social media stars took to stages across the capital Manila ahead of the election on Monday, which pits Vice President Leni Robredo against frontrunner Ferdinand Marcos Jr, the son of the notorious late dictator who ruled the Philippines for 20 years. If opinion…