fa1d5800d9c5e33942b76f6667839a818723dee9
validation: Remove unused boost interruption_point
ActivateBestChain (ABC) is only called in the "msghand" or one of the
RPC threads, neither of which is a boost::thread. However, ABC is also
called in ThreadImport (which currently happens to be a boost::thread).
In all cases, the interruption_point is redundant with the breakpoint in
ABC that triggers when ShutdownRequested()VerifyDB is only called in the main thread ("init") or one of the RPC
threads, neither of which is a boost::thread.
fa3b4f9b8e54ec07aeb2e5e2333da3e784f7be12
validation: Make VerifyDB level 4 interruptible
This is a backport of core#19142