PARIS — On a day of commemoration of the end of World War II in Europe, the war in Ukraine was marked by posturing and signaling on Sunday, as each side ramped up its rhetoric and resolve.Leaders of the world’s wealthiest democracies vowed to end their dependence on Russian energy and ensure that Russia does not triumph in its “unprovoked, unjustifiable and illegal aggression,” as President Vladimir V. Putin pursued his indiscriminate bombardment of eastern Ukraine and orchestrated celebrations for Russia’s Victory Day holiday on Monday.A statement by the Group of 7 major industrialized nations said that on a day...