Fix PoW mining in mixed PoS/PoW, fix orphaned stake tx

src/wallet/wallet.cpp

@@ -1358,6 +1358,18 @@ bool CWallet::IsFromMe(const uint256& nullifier) const
     return false;
 }
 
+void CWallet::EraseFromWallet(const uint256 &hash)
+{
+    if (!fFileBacked)
+        return;
+    {
+        LOCK(cs_wallet);
+        if (mapWallet.erase(hash))
+            CWalletDB(strWalletFile).EraseTx(hash);
+    }
+    return;
+}
+
 void CWallet::GetNoteWitnesses(std::vector<JSOutPoint> notes,
                                std::vector<boost::optional<ZCIncrementalWitness>>& witnesses,
                                uint256 &final_anchor)

src/wallet/wallet.h

@@ -995,6 +995,7 @@ public:
     bool UpdateNullifierNoteMap();
     void UpdateNullifierNoteMapWithTx(const CWalletTx& wtx);
     bool AddToWallet(const CWalletTx& wtxIn, bool fFromLoadWallet, CWalletDB* pwalletdb);
+    void EraseFromWallet(const uint256 &hash);
     void SyncTransaction(const CTransaction& tx, const CBlock* pblock);
     bool AddToWalletIfInvolvingMe(const CTransaction& tx, const CBlock* pblock, bool fUpdate);
     void EraseFromWallet(const uint256 &hash);