tests: Initialize sigops draining script with bytes in feature_taproot

The sigops draining script in feature_taproot's block_submit was
initialized with a list that would end up always being iterated by
CScript's constructor. Since this list is very large, a lot of time
would be wasted. By creating and passing a bytes object initialized from
that list, we can avoid this iteration and dramatically improve the
runtime of feature_taproot.

Author: achow101

test/functional/feature_taproot.py

@@ -1292,7 +1292,7 @@ def block_submit(self, node, txs, msg, err_msg, cb_pubkey=None, fees=0, sigops_w
         # It is not impossible to fit enough tapscript sigops to hit the old 80k limit without
         # busting txin-level limits. We simply have to account for the p2pk outputs in all
         # transactions.
-        extra_output_script = CScript([OP_CHECKSIG]*((MAX_BLOCK_SIGOPS_WEIGHT - sigops_weight) // WITNESS_SCALE_FACTOR))
+        extra_output_script = CScript(bytes([OP_CHECKSIG]*((MAX_BLOCK_SIGOPS_WEIGHT - sigops_weight) // WITNESS_SCALE_FACTOR)))
 
         coinbase_tx = create_coinbase(self.lastblockheight + 1, pubkey=cb_pubkey, extra_output_script=extra_output_script, fees=fees)
         block = create_block(self.tip, coinbase_tx, self.lastblocktime + 1, txlist=txs)