TAS-102 Active Not Recruiting Phase 2 Trials for Cholangiocarcinomas / Stage IVB Gallbladder Cancer AJCC v7 / Stage III Gallbladder Cancer AJCC V7 / Stage IV Gallbladder Cancer AJCC v7 / Stage IVA Gallbladder Cancer AJCC v7 / Stage IIIB Gallbladder Cancer AJCC v7 / Stage IIIA Gallbladder Cancer AJCC v7 Treatment