Fix bug in verifier: soft fail was hiding hard fail.

Rationale:
Dexfuzzing found a situation where a soft fail (modifying
a final field) was hiding a hard fail (type error on that
field), which caused a crash in the compiler later on.
Also added a crash-before/pass-after regression test,
so we don't add the return by accident later.

BUG=28908555

Change-Id: I0cdc400be22a2d9eb00db8c8c6b25a85fbdac993