ART: Fix invalid access and DCHECK in verifier

If we get a throwing failure when setting types from the signature,
the work instruction index is still invalid. Do not try to copy the
line then.

As a throwing failure might happen in the above instance, but the
flow analysis expects to have a cleared failure flag before processing
each instruction, clear the flag.

Bug: 21645819
Bug: 22080519
Change-Id: I224c4dad98fa5bb50e62210f0ee30c0dd020e3a6