Fix: e2e defunct process

[0xcb9ff9]

Description

• fix e2e test created defunct process
• Unix environment kill process group
• fix protocol/testing.go data directory path empty (use t.TempDir() temp directory)
• fix mockStore.GetReceiptsByHash concurrent error
• never use the same port

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

[codecov-commenter]

Codecov Report

Merging #192 (65e8fc7) into dev (ec87ccd) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 65e8fc7 differs from pull request most recent head ff2c024. Consider uploading reports for the commit ff2c024 to get more accurate results

@@           Coverage Diff           @@
##              dev     #192   +/-   ##
=======================================
  Coverage   51.43%   51.43%           
=======================================
  Files         114      114           
  Lines       16948    16950    +2     
=======================================
+ Hits         8717     8719    +2     
  Misses       7491     7491           
  Partials      740      740           

Impacted Files	Coverage Δ
protocol/testing.go	83.54% <100.00%> (+0.14%)	⬆️

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[DarianShawn]

Great job, man. 💯
It fixes the test probabilistic failure that we had long missed.

A minor correction would make it better.