Early counting on Saturday in India’s most populous state showed Prime Minister Narendra Modi’s party leading in the country’s most important electoral test since the 2014 general election. If the Bharatiya Janata Party does wrest control of Uttar Pradesh it would be an endorsement of Modi’s stewardship of Asia’s third-largest economy after his high-risk decision last November to scrap high-value banknotes worth 86 percent of the cash in circulation.