Potential PSBT issues found by the PSBT fuzzer (#17136):

```
$ src/test/fuzz/psbt
…
==8112==ERROR: AddressSanitizer: heap-use-after-free on address 0x6070001083f0 at pc 0x55a5d650f41b bp 0x7ffe03cc3c90 sp 0x7ffe03cc3c88
READ of size 8 at 0x6070001083f0 thread T0
    #0 0x55a5d650f41a in CTxOut::operator=(CTxOut const&) src/./primitives/transaction.h:133:7
    #1 0x55a5d8362e8d in PartiallySignedTransaction::GetInputUTXO(CTxOut&, int) const src/psbt.cpp:72:14
    #2 0x55a5d6dae419 in AnalyzePSBT(PartiallySignedTransaction) src/node/psbt.cpp:32:19
    #3 0x55a5d64b27d7 in test_one_input(std::vector<unsigned char, std::allocator<unsigned char> > const&) src/test/fuzz/psbt.cpp:28:35
…

$ src/test/fuzz/psbt
…
AddressSanitizer:DEADLYSIGNAL
=================================================================
==22238==ERROR: AddressSanitizer: SEGV on unknown address 0x6098001079e0 (pc 0x55880d55c50f bp 0x7fff8d03d8f0 sp 0x7fff8d03d860 T0)
==22238==The signal is caused by a READ memory access.
    #0 0x55880d55c50e in CTxOut::operator=(CTxOut const&) src/./primitives/transaction.h:133:7
    #1 0x55880f3b6a83 in SignPSBTInput(SigningProvider const&, PartiallySignedTransaction&, int, int, SignatureData*, bool) src/psbt.cpp:262:14
    #2 0x55880f3b81ff in FinalizePSBT(PartiallySignedTransaction&) src/psbt.cpp:311:21
    #3 0x55880d500ee9 in test_one_input(std::vector<unsigned char, std::allocator<unsigned char> > const&) src/test/fuzz/psbt.cpp:62:11
…

$ src/test/fuzz/psbt
…
node/psbt.cpp:82:26: runtime error: signed integer overflow: 7857790368227518552 + 6582955728264977243 cannot be represented in type 'long'
    #0 0x55a8b66b13ee in AnalyzePSBT(PartiallySignedTransaction)::$_0::operator()(long, CTxOut const&) const src/node/psbt.cpp:82:26
    #1 0x55a8b66b1043 in long std::accumulate<__gnu_cxx::__normal_iterator<CTxOut*, std::vector<CTxOut, std::allocator<CTxOut> > >, long, AnalyzePSBT(PartiallySignedTransaction)::$_0>(__gnu_cxx::__normal_iterator<CTxOut*, std::vector<CTxOut, std::allocator<CTxOut> > >, __gnu_cxx::__normal_iterator<CTxOut*, std::vector<CTxOut, std::allocator<CTxOut> > >, long, AnalyzePSBT(PartiallySignedTransaction)::$_0) /usr/bin/../lib/gcc/x86_64-linux-gnu/7.4.0/../../../../include/c++/7.4.0/bits/stl_numeric.h:154:11
    #2 0x55a8b66aeecf in AnalyzePSBT(PartiallySignedTransaction) src/node/psbt.cpp:80:27
    #3 0x55a8b5db1a17 in test_one_input(std::vector<unsigned char, std::allocator<unsigned char> > const&) src/test/fuzz/psbt.cpp:28:35
…

$ src/test/fuzz/psbt
…
policy/feerate.cpp:18:34: runtime error: signed integer overflow: -7497025602362688435 * 1000 cannot be represented in type 'long'
    #0 0x5587f480b863 in CFeeRate::CFeeRate(long const&, unsigned long) src/policy/feerate.cpp:18:34
    #1 0x5587f327051f in AnalyzePSBT(PartiallySignedTransaction) src/node/psbt.cpp:116:22
    #2 0x5587f2971ac7 in test_one_input(std::vector<unsigned char, std::allocator<unsigned char> > const&) src/test/fuzz/psbt.cpp:28:35
…
```
CDataStream s_rs1(ParseHex("475221029583bf39ae0a609747ad199addd634fa6108559d6c5cd39b4c2183f1ab96e07f2102dab61ff49a14db6a7d02b0cd1fbb78fc4b18312b5b4e54dae4dba2fbfef536d752ae"), SER_NETWORK, PROTOCOL_VERSION);
    s_rs1 >> rs1;
    spk_man->AddCScript(rs1);
    CScript rs2;
    CDataStream s_rs2(ParseHex("2200208c2353173743b595dfb4a07b72ba8e42e3797da74e87fe7d9d7497e3b2028903"), SER_NETWORK, PROTOCOL_VERSION);
    s_rs2 >> rs2;
    spk_man->AddCScript(rs2);
    CScript ws1;
    CDataStream s_ws1(ParseHex("47522103089dc10c7ac6db54f91329af617333db388cead0c231f723379d1b99030b02dc21023add904f3d6dcf59ddb906b0dee23529b7ffb9ed50e5e86151926860221f0e7352ae"), SER_NETWORK, PROTOCOL_VERSION);
    s_ws1 >> ws1;
    spk_man->AddCScript(ws1);
    
    CKey key = DecodeSecret("5KSSJQ7UNfFGwVgpCZDSHm5rVNhMFcFtvWM3zQ8mW4qNDEN7LFd"); 
    CPubKey master_pub_key = spk_man->DeriveNewSeed(key);
    spk_man->SetHDSeed(master_pub_key);
    spk_man->NewKeyPool();
    
    PartiallySignedTransaction psbtx;
    CDataStream ssData(ParseHex("70736274ff01009a020000000258e87a21b56daf0c23be8e7070456c336f7cbaa5c8757924f545887bb2abdd750000000000ffffffff838d0427d0ec650a68aa46bb0b098aea4422c071b2ca78352a077959d07cea1d0100000000ffffffff0270aaf00800000000160014d85c2b71d0060b09c9886aeb815e50991dda124d00e1f5050000000016001400aea9a2e5f0f876a588df5546e8742d1d87008f000000000000000000"), SER_NETWORK, PROTOCOL_VERSION);
    ssData >> psbtx;
    
    bool complete = true;
    BOOST_REQUIRE_EQUAL(TransactionError::OK, FillPSBT(&m_wallet, psbtx, complete, SIGHASH_ALL, false, true));
    
    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
    ssTx << psbtx;
    std::string final_hex = HexStr(ssTx.begin(), ssTx.end());
    BOOST_CHECK_EQUAL(final_hex, "70736274ff01009a020000000258e87a21b56daf0c23be8e7070456c336f7cbaa5c8757924f545887bb2abdd750000000000ffffffff838d0427d0ec650a68aa46bb0b098aea4422c071b2ca78352a077959d07cea1d0100000000ffffffff0270aaf00800000000160014d85c2b71d0060b09c9886aeb815e50991dda124d00e1f5050000000016001400aea9a2e5f0f876a588df5546e8742d1d87008f00000000000100bb0200000001aad73931018bd25f84ae400b68848be09db706eac2ac18298babee71ab656f8b0000000048473044022058f6fc7c6a33e1b31548d481c826c015bd30135aad42cd67790dab66d2ad243b02204a1ced2604c6735b6393e5b41691dd78b00f0c5942fb9f751856faa938157dba01feffffff0280f0fa020000000017a9140fb9463421696b82c833af241c78c17ddbde493487d0f20a270100000017a91429ca74f8a08f81999428185c97b5d852e4063f6187650000000104475221029583bf39ae0a609747ad199addd634fa6108559d6c5cd39b4c2183f1ab96e07f2102dab61ff49a14db6a7d02b0cd1fbb78fc4b18312b5b4e54dae4dba2fbfef536d752ae2206029583bf39ae0a609747ad199addd634fa6108559d6c5cd39b4c2183f1ab96e07f10d90c6a4f000000800000008000000080220602dab61ff49a14db6a7d02b0cd1fbb78fc4b18312b5b4e54dae4dba2fbfef536d710d90c6a4f0000008000000080010000800001012000c2eb0b0000000017a914b7f5faf40e3d40a5a459b1db3535f2b72fa921e88701042200208c2353173743b595dfb4a07b72ba8e42e3797da74e87fe7d9d7497e3b2028903010547522103089dc10c7ac6db54f91329af617333db388cead0c231f723379d1b99030b02dc21023add904f3d6dcf59ddb906b0dee23529b7ffb9ed50e5e86151926860221f0e7352ae2206023add904f3d6dcf59ddb906b0dee23529b7ffb9ed50e5e86151926860221f0e7310d90c6a4f000000800000008003000080220603089dc10c7ac6db54f91329af617333db388cead0c231f723379d1b99030b02dc10d90c6a4f00000080000000800200008000220203a9a4c37f5996d3aa25dbac6b570af0650394492942460b354753ed9eeca5877110d90c6a4f000000800000008004000080002202027f6399757d2eff55a136ad02c684b1838b6556e5f1b6b34282a94b6b5005109610d90c6a4f00000080000000800500008000");
}
BOOST_AUTO_TEST_CASE(parse_hd_keypath)