phabricator: update hgmatcher to cope with the new data format The new conduit format can't be matched by the existing matcher since it shifts all the data into an urlencoded string of JSON, the order of which isn't stable between runs. Instead detect JSON values of params and load them into python dicts, which python will then naturally deep-equal compare. Differential Revision: https://phab.mercurial-scm.org/D7055