Tx: Cache sender

[jochem-brouwer]

I did a test profile run and noticed that especially ecrecover takes relatively long. We should only do this once for frozen txs, since the sender cannot change.

Note: this halves the amount of ecrecover calls in VM's runBlock (two calls: first in block.validateData which tx.getValidationErrors which checks the signature, and then in runTx because we need to see if the sender has enough data, and of course have to setup EVMs ORIGIN / CALLER for the transaction).

[codecov]

Codecov Report

Merging #2985 (5c0cc6a) into master (f5dcf4a) will increase coverage by 0.08%.
Report is 1 commits behind head on master.
The diff coverage is 100.00%.

Additional details and impacted files

Flag	Coverage Δ
block	88.66% <ø> (ø)
blockchain	92.58% <ø> (ø)
client	87.37% <ø> (ø)
common	98.61% <100.00%> (+0.05%)	⬆️
ethash	∅ <ø> (∅)
evm	70.43% <ø> (ø)
rlp	∅ <ø> (∅)
statemanager	84.43% <ø> (ø)
trie	90.03% <ø> (+0.50%)	⬆️
tx	95.97% <100.00%> (+0.09%)	⬆️
util	86.78% <ø> (ø)
vm	79.20% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[ScottyPoi]

Nice catch 👍

LGTM

[holgerd77]

Yes, agree, great catch! 👍

Will merge.