WASHINGTON — Now it’s Newt’s turn to take the heat. Former House Speaker Newt Gingrich, rising in the polls for the Republican presidential nomination, is coming under fire for a $300,000 consulting contract he got with home-loan giant Freddie Mac before the housing market collapse. Gingrich, asked at a Republican debate Saturday night about what he did under the contract, said he lectured company officials on their lending practices. “As I said to them at the time, ‘This is a bubble. This is insane. This is impossible,’ ” he said he told them. Gingrich, who has slammed Democrats Chris Dodd...