For a generation weaned on sitcoms of the 21st century, the deaths this week of George Segal and Jessica Walter conjured images of the actors playing two of America’s most lovably eccentric grandparents: Segal as “Pops” Solomon on “The Goldbergs” and Walter as Lucille Bluth on “Arrested Development,” where simply by raising a martini and fixing a withering glance at her husband or one of her children, she launched a thousand memes lacerating anyone who ever said anything stupid on the Internet.