The 70-year-old ‘Glass’ actor aims to work well into his 80s — if Marvel and the rest of Hollywood can afford him: ‘I’m a gunslinger now.‘ — By Seth Abramovitch He arrives exactly on schedule, not a minute early, not a minute late, and comes dressed in character: Armani cashmere shirt, translucent Alain Mikli eyeglasses and, of course, a Kangol cap. There are no formalities, no handshakes, no, “Hi, nice to meet you, I’m Samuel L. Jackson.”…