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/mining_basic.py

@@ -425,7 +425,6 @@ class MiningTest(BitcoinTestFramework):
         coinbase_tx = create_coinbase(height=next_height)
         # sequence numbers must not be max for nLockTime to have effect
         coinbase_tx.vin[0].nSequence = 2**32 - 2
-        coinbase_tx.rehash()
 
         block = CBlock()
         block.nVersion = tmpl["version"]
@@ -447,7 +446,6 @@ class MiningTest(BitcoinTestFramework):
         self.log.info("getblocktemplate: Test bad input hash for coinbase transaction")
         bad_block = copy.deepcopy(block)
         bad_block.vtx[0].vin[0].prevout.hash += 1
-        bad_block.vtx[0].rehash()
         assert_template(node, bad_block, 'bad-cb-missing')
 
         self.log.info("submitblock: Test bad input hash for coinbase transaction")
@@ -481,7 +479,6 @@ class MiningTest(BitcoinTestFramework):
         bad_block = copy.deepcopy(block)
         bad_tx = copy.deepcopy(bad_block.vtx[0])
         bad_tx.vin[0].prevout.hash = 255
-        bad_tx.rehash()
         bad_block.vtx.append(bad_tx)
         assert_template(node, bad_block, 'bad-txns-inputs-missingorspent')
         assert_submitblock(bad_block, 'bad-txns-inputs-missingorspent')
@@ -489,7 +486,6 @@ class MiningTest(BitcoinTestFramework):
         self.log.info("getblocktemplate: Test nonfinal transaction")
         bad_block = copy.deepcopy(block)
         bad_block.vtx[0].nLockTime = 2**32 - 1
-        bad_block.vtx[0].rehash()
         assert_template(node, bad_block, 'bad-txns-nonfinal')
         assert_submitblock(bad_block, 'bad-txns-nonfinal')
 
@@ -563,7 +559,6 @@ class MiningTest(BitcoinTestFramework):
 
         bad_block_lock = copy.deepcopy(block)
         bad_block_lock.vtx[0].nLockTime = 2**32 - 1
-        bad_block_lock.vtx[0].rehash()
         bad_block_lock.hashMerkleRoot = bad_block_lock.calc_merkle_root()
         bad_block_lock.solve()
         assert_equal(node.submitblock(hexdata=bad_block_lock.serialize().hex()), 'bad-txns-nonfinal')