CI: Increase parallelism without changing resource_class for faster builds

[michaeldiamant]

Provides an alternative to #4427 that cuts estimated costs by ~50% in exchange for longer build durations.

Based on the sample run times in https://app.circleci.com/pipelines/github/algorand/go-algorand?branch=circleci_consolidate_parallelism_alt, we can expect build durations of ~18-22min.

[codecov]

Codecov Report

Merging #4448 (e0ff19d) into circleci_consolidate_parallelism (a311590) will increase coverage by 0.02%.
The diff coverage is n/a.

@@                         Coverage Diff                          @@
##           circleci_consolidate_parallelism    #4448      +/-   ##
====================================================================
+ Coverage                             55.22%   55.25%   +0.02%     
====================================================================
  Files                                   398      398              
  Lines                                 50165    50165              
====================================================================
+ Hits                                  27706    27721      +15     
+ Misses                                20138    20128      -10     
+ Partials                               2321     2316       -5     

Impacted Files	Coverage Δ
catchup/service.go	69.38% <0.00%> (-1.73%)	⬇️
ledger/tracker.go	74.78% <0.00%> (ø)
ledger/accountdb.go	72.74% <0.00%> (+0.15%)	⬆️
ledger/acctonline.go	79.41% <0.00%> (+0.52%)	⬆️
network/requestTracker.go	71.12% <0.00%> (+0.86%)	⬆️
network/wsPeer.go	71.23% <0.00%> (+3.01%)	⬆️
ledger/roundlru.go	96.22% <0.00%> (+5.66%)	⬆️

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[michaeldiamant]

Basing off of master rather than #4427. Based on live discussion, we agreed to favor this PR over #4427.

[jannotti]

I think this is what we agreed to.

[algojack]

lgtm