AVM: Clearer cost benchmarks, and a nice optimization of b== and b<

[jannotti]

Cleans up benchmarks in a way that should let us assign costs more easily, especially for costs that differ based on input size.

One such benchmark showed that "byte math compares" were all significantly improved by avoiding the use of big.Int, so that change is included.

[codecov]

Codecov Report

Merging #5010 (885c02d) into master (eddf773) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #5010      +/-   ##
==========================================
- Coverage   53.63%   53.62%   -0.02%     
==========================================
  Files         432      432              
  Lines       54057    54060       +3     
==========================================
- Hits        28996    28992       -4     
- Misses      22812    22820       +8     
+ Partials     2249     2248       -1     

Impacted Files	Coverage Δ
data/transactions/logic/eval.go	90.17% <100.00%> (+0.01%)	⬆️
ledger/blockqueue.go	85.63% <0.00%> (-2.88%)	⬇️
crypto/merkletrie/trie.go	66.42% <0.00%> (-2.19%)	⬇️
crypto/merkletrie/node.go	91.62% <0.00%> (-1.87%)	⬇️
ledger/tracker.go	74.26% <0.00%> (-0.85%)	⬇️
catchup/service.go	69.08% <0.00%> (-0.73%)	⬇️
ledger/acctupdates.go	69.24% <0.00%> (-0.25%)	⬇️
network/wsNetwork.go	64.92% <0.00%> (+0.17%)	⬆️
catchup/peerSelector.go	100.00% <0.00%> (+1.04%)	⬆️
agreement/proposalManager.go	98.03% <0.00%> (+1.96%)	⬆️
... and 2 more

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