x/evm/keeper: use the fastest slice making idiom for Keeper.EthereumTx.Logs

[odeke-em]

Uses the fastest slice making idiom of creating the well known
size of a slice using

make([]sdk.Attribute, len(response.Logs))
for i, log := range response.Logs {
    txLogAttrs[i] = ...
}

instead of

make([]sdk.Attribute, 0)
for _, log := range response.Logs {
    txLogAttrs = append(txLogAttrs, ...)
}

which had a few problems:

1. Using 0 for size then appending is quite slow yet we know the exact size
2. Using append instead of indexing is slower

If we examine the advisory at https://bencher.orijtech.com/perfclinic/sliceupdate/
and the verdict at https://bencher.orijtech.com/perfclinic/sliceupdate/#verdict
this new scheme shows a massive improvement in that call site.

Fixes #825

[fedekunze]

LGTM, can you add a changelog entry?

[codecov]

Codecov Report

Merging #827 (6b265ab) into main (4ee1d86) will not change coverage.
The diff coverage is 100.00%.

❗ Current head 6b265ab differs from pull request most recent head 46a47df. Consider uploading reports for the commit 46a47df to get more accurate results

@@           Coverage Diff           @@
##             main     #827   +/-   ##
=======================================
  Coverage   57.31%   57.31%           
=======================================
  Files          72       72           
  Lines        5984     5984           
=======================================
  Hits         3430     3430           
  Misses       2357     2357           
  Partials      197      197           

Impacted Files	Coverage Δ
x/evm/keeper/msg_server.go	73.58% <100.00%> (ø)

[odeke-em]

LGTM, can you add a changelog entry?

Done, please take a look and thank you @fedekunze!