There turned out to be a mismatch in the tx output counts which caused
'ConnectBlockMixedEcdsaSchnorr' benchmark to run slower than
'ConnectBlockAllEcdsa' and 'ConnectBlockAllSchnorr'. This commit makes
the tx output counts uniform across all benchmarks.
This commit also renames the 'taproot_tx' variable to 'tx' to reflect
that this variable represents a general tx and not just a taproot tx.
Measure ConnectBlock performance for
- blocks containing only schnorr sigs
- blocks containing both schnorr and ecdsa sigs
- blocks containing only ecdsa sigs
This will allow testing and measurement of performance improvement for features like
batch verification of schnorr signatures