Risk comes with any change of employer which brings a reasonable sense of worry for one's personal (financial) security. For this reason alone, I would recommend not burning this bridge. Give whatever notice your current employer asks for (not a day more) and let the cards fall where they do.

Not to be a pessimist, nor imply you may not pass, but as someone mentioned the reason you leave may be as a result of your failure and nothing to do with a hiring freeze. Crap happens and it's best to be as prepared for it as possible.