Remove all glmark2 symlink hacks (Bugfix)

[tomli380576]

Description

This is the followup PR for #2281 that removes all symlink hacks.

Resolved issues

1. Remove all symlink hacks
2. CHECKBOX_RUNTIME has multiple lines. Added a function that explicitly searches for $SNAP/checkbox-runtime

Documentation

Tests

C3 submissions:

• classic desktop
• ubuntu frame

[codecov]

Codecov Report

❌ Patch coverage is 61.53846% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 54.46%. Comparing base (f8136c5) to head (7da289e).
⚠️ Report is 25 commits behind head on main.

Files with missing lines	Patch %	Lines
providers/base/bin/reboot_check_test.py	50.00%	4 Missing and 1 partial ⚠️

❌ Your patch status has failed because the patch coverage (61.53%) is below the target coverage (90.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2287      +/-   ##
==========================================
- Coverage   54.49%   54.46%   -0.04%     
==========================================
  Files         409      409              
  Lines       43970    43954      -16     
  Branches     8100     8096       -4     
==========================================
- Hits        23961    23938      -23     
- Misses      19190    19197       +7     
  Partials      819      819              

Flag	Coverage Δ
provider-base	31.30% <61.53%> (-0.11%)	⬇️

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[tomli380576]

Closing this since it contains workarounds for #2295