Merge bitcoin/bitcoin#24145: mempool: Clear vTxHashes when mapTx is cleared

9d65ad365c Clear vTxHashes when mapTx is cleared (Peter Bushnell)

Pull request description:

  vTxHashes is a vector of all entries in mapTx, if you clear one you should clear the other, lest someone try to use the txiter in vTxHashes which would result in a segfault.

ACKs for top commit:
  laanwj:
    Code review ACK 9d65ad365c

Tree-SHA512: 6832755e43ab7f528b46817aeadcb6ffdc965b97f59ab96bb053dedbb7e68155ba3db52286355dca33b509237f80eda249760b26db493762bc50d8e2cef16d8f

src/txmempool.cpp

@@ -694,6 +694,7 @@ void CTxMemPool::removeForBlock(const std::vector<CTransactionRef>& vtx, unsigne
 
 void CTxMemPool::_clear()
 {
+    vTxHashes.clear();
     mapTx.clear();
     mapNextTx.clear();
     totalTxSize = 0;