By John Revill and Anton Bridge ZURICH/TOKYO (Reuters) -SoftBank Group has agreed to buy the robotics business of Swiss engineering group ABB in a $5.4 billion deal, as the Japanese investor forges ahead with a strategy to fuse robotics and artificial intelligence. The acquisition, announced on Wednesday, is the latest by founder and CEO Masayoshi Son to establish Softbank as a core player in the development of artificial intelligence. SoftBank pushed into humanoid robotics a decade ago with its Pepper ...