Fix missing cs_main lock for GuessVerificationProgress()

src/validation.cpp

@@ -4659,6 +4659,7 @@ bool DumpMempool(void)
 }
 
 //! Guess how far we are in the verification process at the given block index
+//! require cs_main if pindex has not been validated yet (because nChainTx might be unset)
 double GuessVerificationProgress(const ChainTxData& data, const CBlockIndex *pindex) {
     if (pindex == nullptr)
         return 0.0;