SIERRA MADRE, Calif. Nestled into this small city of 12,000, a suburb of Pasadena in Los Angeles County is the storied Sierra Madre Playhouse, a minor jewel in the diadem of Southern California’s regional theater scene. A company that ranks a step or two above the pejorative-sounding term “community theater,” it often presents challenging work on difficult, controversial themes and owns a proud history of world premieres.