Merge bitcoin/bitcoin#27200: test: psbt: check non-witness UTXO removal for segwit v1 input

3dd2f6461b test: psbt: check non-witness UTXO removal for segwit v1 input (Sebastian Falbesoner)
dd78e3fa43 test: speedup rpc_psbt.py by whitelisting peers (immediate tx relay) (Sebastian Falbesoner)
e194e3e93d test: PSBT: eliminate magic numbers for global unsigned tx key (0) (Sebastian Falbesoner)

Pull request description:

  This PR adds missing test coverage for dropping non-witness UTXOs from PSBTs for segwit v1+ inputs (see commit 103c6fd279). The formerly [disabled](4600479058) method `test_utxo_conversion` is re-enabled and adapted to spend a Taproot (`bech32m`) instead of a wrapped SegWit (`p2sh-segwit`) output. Note that in contrast to the original test, we have to add the non-witness UTXO manually here using the test framework's PSBT module, since the constructing node knows that the output is segwit v1 and hence doesn't add the non-witness UTXO in the first place (see also [BIP371]( https://github.com/bitcoin/bips/blob/master/bip-0371.mediawiki#user-content-UTXO_Types)).

  I strongly assume that most wallets would behave the same as Bitcoin Core here and wouldn't create PSBTs with non-witness UTXOs for Taproot inputs, but it's still good to test everything works as expected if it's still done and that the non-witness UTXO is simply dropped in that case.

  The first two commits contain a small refactor (magic number elimination in PSBT module) and test speedup of ~2-3x (using whitelisting peers / immediate tx relay).

ACKs for top commit:
  achow101:
    ACK 3dd2f6461b
  instagibbs:
    ACK 3dd2f6461b

Tree-SHA512: b8d7f7ea5d7d21def024b70dfca61991cc96a4193be8857018b4d7cf3ca1465d185619fd4a77623803d9da309aa489c53273e9b7683d970ce12e2399b5b50031

test/functional/test_framework/psbt.py

@@ -105,8 +105,8 @@ class PSBT:
     def deserialize(self, f):
         assert f.read(5) == b"psbt\xff"
         self.g = from_binary(PSBTMap, f)
-        assert 0 in self.g.map
-        self.tx = from_binary(CTransaction, self.g.map[0])
+        assert PSBT_GLOBAL_UNSIGNED_TX in self.g.map
+        self.tx = from_binary(CTransaction, self.g.map[PSBT_GLOBAL_UNSIGNED_TX])
         self.i = [from_binary(PSBTMap, f) for _ in self.tx.vin]
         self.o = [from_binary(PSBTMap, f) for _ in self.tx.vout]
         return self
@@ -115,8 +115,8 @@ class PSBT:
         assert isinstance(self.g, PSBTMap)
         assert isinstance(self.i, list) and all(isinstance(x, PSBTMap) for x in self.i)
         assert isinstance(self.o, list) and all(isinstance(x, PSBTMap) for x in self.o)
-        assert 0 in self.g.map
-        tx = from_binary(CTransaction, self.g.map[0])
+        assert PSBT_GLOBAL_UNSIGNED_TX in self.g.map
+        tx = from_binary(CTransaction, self.g.map[PSBT_GLOBAL_UNSIGNED_TX])
         assert len(tx.vin) == len(self.i)
         assert len(tx.vout) == len(self.o)
 
@@ -130,7 +130,7 @@ class PSBT:
         for m in self.i + self.o:
             m.map.clear()
 
-        self.g = PSBTMap(map={0: self.g.map[0]})
+        self.g = PSBTMap(map={PSBT_GLOBAL_UNSIGNED_TX: self.g.map[PSBT_GLOBAL_UNSIGNED_TX]})
 
     def to_base64(self):
         return base64.b64encode(self.serialize()).decode("utf8")