[backport] Removed restriction on final vars, SI-2418.

Backport of b79c7600544db9964c228b94a2f70f3ed854f89b

The original fix for SI-2418 excluded final vars entirely, but
the problem was not final vars per se, but the emission of ACC_FINAL
in combination with ACC_VOLATILE.  Since vars never get ACC_FINAL
now, this is no longer an issue.

review @paulp since it's a backport of his code