AP: The Texas-based oil companies that are the primary backers of a November ballot effort to suspend California’s global warming law are among the state’s biggest polluters, according to a report issued Tuesday by two groups advocating for inner-city residents. Valero Energy Corp. and Tesoro Corp. have contributed more than $4.5 million to Proposition 23, which seeks to suspend a 2006 law intended to reduce greenhouse gas emissions. Their contributions represent nearly 75 percent of the …