ABC News' Matthew Jaffe Reports: Sen. Joe Biden, D-Del., on Sunday guaranteed that if elected, Sen. Barack Obama., D-Ill., will be tested by an international crisis within his first six months in power and he will need supporters to stand by him as he makes tough, and possibly unpopular, decisions. Watch, we're gonna have an international crisis, a generated crisis, to test the mettle of this guy." "I can give you at least four or five scenarios from where it might originate," Biden said to Emerald City supporters, mentioning the Middle East and Russia as possibilities. "And he's gonna need...