fix(unit-test): fixes TestDownloader flaky test

[raj-prince]

Description

• Fixed infinite loop in waitForCrcCheckToBeCompleted()
• Fixed race condition in Test_GetJob_Concurrent()
• Fixed file system conflicts
• Move to testify from ogle test.

Link to the issue in case of a bug fix.

Testing details

1. Manual - NA
2. Unit tests - NA
3. Integration tests - NA

Any backward incompatible change? If so, please explain.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.18%. Comparing base (513df1a) to head (26d5d5b).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4195      +/-   ##
==========================================
- Coverage   83.19%   83.18%   -0.02%     
==========================================
  Files         153      153              
  Lines       18716    18716              
==========================================
- Hits        15570    15568       -2     
- Misses       2577     2578       +1     
- Partials      569      570       +1     

Flag	Coverage Δ
unittests	83.18% <ø> (-0.02%)	⬇️

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