Legislation to open coveted offshore oil fields in Brazil to foreign players took a major step forward this week, but still faces fierce resistance from opponents who consider the measure an affront to the country’s control of a prized natural resource. Brazil’s Senate late Wednesday approved by a 40-to-26 vote a bill aimed at spurring global competition for massive oil reserves located in deep waters about 200 miles off Brazil’s southeastern coast. The bill still faces a potentially long battle in the…