TEL AVIV, Israel — U.S. President Joe Biden called Prime Minister Benjamin Netanyahu’s handling of the war in Gaza a mistake and called for his government to flood the beleaguered territory with aid, ramping up pressure on Israel to reach a cease-fire and widening a rift between the two staunch allies. Palestinians in Gaza marked a muted start to the Eid al-Fitr holiday, with parents visiting the graves of sons and daughters killed in the war.