By Tim Reid and Jason Lange PHOENIX (Reuters) – Democrats will hold onto control of the U.S. Senate after Senator Catherine Cortez Masto won re-election in Nevada, Edison Research projected on Saturday, handing a major victory to President Joe Biden. Still, Republicans remained close to winning control of the U.S. House of Representatives as officials continued counting ballots cast in Tuesday’s U.S. midterm elections. Cortez Masto narrowly defeated Republican challenger Adam Laxalt, a former state attorney general who was endorsed by former President Donald Trump. With Masto’s victory on the …