Fix handling of unresolved references in verifier.

The verifier should not treat use of unresolved references as a reason to reject
the entire class. Instead, the verifier treats the instruction as a throw. If
that class is run, the interpreter with extra checks will throw an exception.

Bug: 10457426

(cherry picked from commit a3faaf4b)

Change-Id: I161bfdbfa116890ffa9e7a593c756229bd939eb4