Every politician in Washington is promising to alleviate the “affordability crisis.”   But nobody told that to the trial lawyers and federal regulators — who have dusted off a century-old law to sue companies for the high crime of lowering consumer prices. No joke. We’re referring to an all-but-forgotten legal relic from the 1930s called the Robinson-Patman Act. We bet you’ve never heard of it. That law prohibits a seller from charging lower prices for the same products to different retail