test: remove bare CTransaction .rehash()/.calc_sha256() calls

Since the previous commit, CTransaction object calls to the
methods `.rehash()` and `.calc_sha256()` are effectively no-ops
if the returned value is not used, so we can just remove them.

test/functional/test_framework/blocktools.py

@@ -134,7 +134,6 @@ def add_witness_commitment(block, nonce=0):
 
     # witness commitment is the last OP_RETURN output in coinbase
     block.vtx[0].vout.append(CTxOut(0, get_witness_script(witness_root, witness_nonce)))
-    block.vtx[0].rehash()
     block.hashMerkleRoot = block.calc_merkle_root()
     block.rehash()
 
@@ -176,7 +175,6 @@ def create_coinbase(height, pubkey=None, *, script_pubkey=None, extra_output_scr
         coinbaseoutput2.nValue = 0
         coinbaseoutput2.scriptPubKey = extra_output_script
         coinbase.vout.append(coinbaseoutput2)
-    coinbase.calc_sha256()
     return coinbase
 
 def create_tx_with_script(prevtx, n, script_sig=b"", *, amount, output_script=None):
@@ -191,7 +189,6 @@ def create_tx_with_script(prevtx, n, script_sig=b"", *, amount, output_script=No
     assert n < len(prevtx.vout)
     tx.vin.append(CTxIn(COutPoint(prevtx.sha256, n), script_sig, SEQUENCE_FINAL))
     tx.vout.append(CTxOut(amount, output_script))
-    tx.calc_sha256()
     return tx
 
 def get_legacy_sigopcount_block(block, accurate=True):

test/functional/test_framework/messages.py

@@ -682,7 +682,6 @@ class CTransaction:
             return uint256_from_str(hash256(self.serialize_with_witness()))
 
     def is_valid(self):
-        self.calc_sha256()
         for tout in self.vout:
             if tout.nValue < 0 or tout.nValue > 21000000 * COIN:
                 return False
@@ -810,7 +809,6 @@ class CBlock(CBlockHeader):
     def calc_merkle_root(self):
         hashes = []
         for tx in self.vtx:
-            tx.calc_sha256()
             hashes.append(ser_uint256(tx.sha256))
         return self.get_merkle_root(hashes)
 

test/functional/test_framework/script.py

@@ -694,7 +694,6 @@ def sign_input_legacy(tx, input_index, input_scriptpubkey, privkey, sighash_type
     assert err is None
     der_sig = privkey.sign_ecdsa(sighash)
     tx.vin[input_index].scriptSig = bytes(CScript([der_sig + bytes([sighash_type])])) + tx.vin[input_index].scriptSig
-    tx.rehash()
 
 def sign_input_segwitv0(tx, input_index, input_scriptpubkey, input_amount, privkey, sighash_type=SIGHASH_ALL):
     """Add segwitv0 ECDSA signature for a given transaction input. Note that the signature
@@ -703,7 +702,6 @@ def sign_input_segwitv0(tx, input_index, input_scriptpubkey, input_amount, privk
     sighash = SegwitV0SignatureHash(input_scriptpubkey, tx, input_index, sighash_type, input_amount)
     der_sig = privkey.sign_ecdsa(sighash)
     tx.wit.vtxinwit[input_index].scriptWitness.stack.insert(0, der_sig + bytes([sighash_type]))
-    tx.rehash()
 
 # TODO: Allow cached hashPrevouts/hashSequence/hashOutputs to be provided.
 # Performance optimization probably not necessary for python tests, however.