testing: improve 6M asset testing performance

[tsachiherman]

Summary

This PR replaces the usage of the LibGoal with the direct RestClient. The change could have performance implications when running against large sets of data.

Test Plan

This is a test.

[codecov-commenter]

Codecov Report

Merging #3749 (0b5be07) into master (f8a869b) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3749   +/-   ##
=======================================
  Coverage   49.75%   49.75%           
=======================================
  Files         392      392           
  Lines       68746    68746           
=======================================
+ Hits        34204    34205    +1     
- Misses      30776    30778    +2     
+ Partials     3766     3763    -3     

Impacted Files	Coverage Δ
ledger/blockqueue.go	82.18% <0.00%> (-2.88%)	⬇️
network/wsPeer.go	68.33% <0.00%> (-0.28%)	⬇️
network/wsNetwork.go	62.79% <0.00%> (-0.20%)	⬇️
ledger/acctupdates.go	68.42% <0.00%> (ø)
catchup/service.go	69.38% <0.00%> (+0.74%)	⬆️
data/transactions/verify/txn.go	45.02% <0.00%> (+0.86%)	⬆️
data/abi/abi_type.go	88.62% <0.00%> (+0.94%)	⬆️
cmd/algoh/blockWatcher.go	80.95% <0.00%> (+3.17%)	⬆️

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[algonautshant]

Looks great!