(Reuters) - Gains for oil majors and miners pushed London's FTSE 100 into the black on Tuesday, buoyed by hopes of a trade deal between the United States and China, while Primark owner Associated British Foods jumped 6% after strong results. The FTSE 100 advanced 0.3%, after having touched a one-month high earlier in the session, while the mid-cap index was 0.2% higher. A.B.Foods recorded its best one-day spike in more than 10 months after it posted higher annual earnings and said it was..