bench: fix benchmarking after remerges

[algorandskiy]

Summary

While running benchmarks found they do not produce invalid groups anymore. Fixed.

Test Plan

This is a test/bench harness fix.

[codecov]

Codecov Report

Merging #4923 (13ee6c0) into master (e6c3463) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4923      +/-   ##
==========================================
- Coverage   53.52%   53.52%   -0.01%     
==========================================
  Files         431      431              
  Lines       53533    53533              
==========================================
- Hits        28656    28655       -1     
- Misses      22654    22655       +1     
  Partials     2223     2223              

Impacted Files	Coverage Δ
ledger/voters.go	68.65% <0.00%> (-4.48%)	⬇️
ledger/tracker.go	74.26% <0.00%> (-1.69%)	⬇️
ledger/testing/randomAccounts.go	56.00% <0.00%> (-1.24%)	⬇️
ledger/acctonline.go	77.92% <0.00%> (-1.04%)	⬇️
data/transactions/verify/txn.go	73.72% <0.00%> (-0.85%)	⬇️
catchup/service.go	68.59% <0.00%> (-0.73%)	⬇️
network/wsNetwork.go	64.74% <0.00%> (ø)
catchup/peerSelector.go	100.00% <0.00%> (+1.04%)	⬆️
crypto/merkletrie/node.go	93.48% <0.00%> (+1.86%)	⬆️
crypto/merkletrie/trie.go	68.61% <0.00%> (+2.18%)	⬆️
... and 1 more

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[algonautshant]

Great catch!