Bugfix: ensure consistency of m_failed_blocks after reconsiderblock

Author: sdaftuar

src/validation.cpp

@@ -2834,6 +2834,7 @@ bool CChainState::ResetBlockFailureFlags(CBlockIndex *pindex) {
         if (pindex->nStatus & BLOCK_FAILED_MASK) {
             pindex->nStatus &= ~BLOCK_FAILED_MASK;
             setDirtyBlockIndex.insert(pindex);
+            m_failed_blocks.erase(pindex);
         }
         pindex = pindex->pprev;
     }