Avoid serialization of cache data in PHP report

[Slamdunk]

Fix #1009

[codecov]

Codecov Report

Merging #1011 (22c0d82) into 9.2 (78ba572) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##                9.2    #1011      +/-   ##
============================================
+ Coverage     83.98%   84.00%   +0.01%     
- Complexity     1193     1194       +1     
============================================
  Files            61       61              
  Lines          4272     4275       +3     
============================================
+ Hits           3588     3591       +3     
  Misses          684      684              

Files Changed	Coverage Δ
src/CodeCoverage.php	50.36% <100.00%> (+0.36%)	⬆️
src/Report/PHP.php	90.00% <100.00%> (+1.11%)	⬆️

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[Slamdunk]

This PR should be easily mergeable into upstream branch main, so no need for a separate PR as far as I can tell