Tests: Fix t.Parallel() errors in cmd package

[michaeldiamant]

Enables https://github.com/kunwardeep/paralleltest on cmd by fixing linter warnings. Incrementally moves the ball towards greater unit test parallelization, which reduces local + CI test durations.

I vetted for flakiness by running:

go test -race -count 10 ./cmd/...

Notes:

• The PR does not intend to rework all sequential tests into parallel tests. My objective is to enable already available parallelism throughout go-algorand. And then make a pass through remaining sequential tests to see if/where more parallelism exists.

[codecov]

Codecov Report

Merging #4991 (0368212) into master (a688c23) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4991      +/-   ##
==========================================
- Coverage   53.44%   53.42%   -0.02%     
==========================================
  Files         431      431              
  Lines       54364    54364              
==========================================
- Hits        29056    29046      -10     
- Misses      23053    23064      +11     
+ Partials     2255     2254       -1     

Impacted Files	Coverage Δ
ledger/blockqueue.go	82.25% <0.00%> (-2.69%)	⬇️
catchup/service.go	67.76% <0.00%> (-1.18%)	⬇️
network/wsNetwork.go	64.98% <0.00%> (-0.19%)	⬇️
ledger/tracker.go	75.10% <0.00%> (ø)
ledger/acctonline.go	79.16% <0.00%> (+0.52%)	⬆️

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[jdtzmn]

Changes look good! I confirmed locally that the tests pass with the given test command. I found that some of the test files were not caught currently by golangci (see #5046 for more information) and added a commit to address those errors.

[algochoi]

Rebased master into this branch, and checked linter and for flakiness by running the race flag. Also added a commit (0368212) to disable linting on the newest set of cmd tests, which seem to share os variables.