refactor: move scan/mod.rs to scan/tests.rs and scan/test_utils.rs

[aleksandarskrbic]

What changes are proposed in this pull request?

Fixes: #1370

How was this change tested?

[codecov]

Codecov Report

❌ Patch coverage is 98.78935% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.94%. Comparing base (1c29adf) to head (83be5a6).

Files with missing lines	Patch %	Lines
kernel/src/scan/tests.rs	98.39%	2 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1485      +/-   ##
==========================================
- Coverage   84.94%   84.94%   -0.01%     
==========================================
  Files         121      123       +2     
  Lines       32539    32534       -5     
  Branches    32539    32534       -5     
==========================================
- Hits        27641    27636       -5     
  Misses       3556     3556              
  Partials     1342     1342              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.