NEW YORK — U.S. stocks rallied to their highest level in more than a month Tuesday after China’s government moved to inject more life into its economy by cutting taxes and increasing spending. Netflix led a surge in high-tech companies. Health care companies and banks rose as major companies including UnitedHealth and JPMorgan Chase announced their fourth-quarter results. The British pound wobbled after legislators soundly rejected Prime Minister Theresa May’s plan governing the country’s departure from the European Union.