Avoid remapping freed memory in trace sender fallback

[bwoebi]

Description

Fix faulty logic reusing a freed shm handle when sending fails.

Not sure how to test that as the precondition never should fail ... in theory.

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[codecov-commenter]

Codecov Report

Merging #2541 (7c3beba) into master (380774d) will decrease coverage by 1.76%.
Report is 2 commits behind head on master.
The diff coverage is 36.18%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2541      +/-   ##
============================================
- Coverage     78.30%   76.54%   -1.76%     
  Complexity      267      267              
============================================
  Files           112      138      +26     
  Lines         13458    17459    +4001     
  Branches          0      976     +976     
============================================
+ Hits          10538    13364    +2826     
- Misses         2920     3575     +655     
- Partials          0      520     +520     

Flag	Coverage Δ
appsec-extension	69.09% <ø> (?)
tracer-extension	78.69% <36.18%> (+0.46%)	⬆️
tracer-integrations	79.49% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
ext/integrations/integrations.c	97.88% <100.00%> (ø)
ext/priority_sampling/priority_sampling.c	95.02% <100.00%> (ø)
ext/request_hooks.c	93.24% <100.00%> (ø)
ext/handlers_curl.c	85.49% <0.00%> (ø)
ext/sidecar.h	62.50% <0.00%> (ø)
ext/startup_logging.c	89.37% <50.00%> (ø)
ext/comms_php.c	78.94% <33.33%> (ø)
ext/configuration.c	78.46% <0.00%> (ø)
ext/engine_hooks.c	85.18% <0.00%> (ø)
ext/excluded_modules.c	38.88% <0.00%> (ø)
... and 9 more

... and 34 files with indirect coverage changes

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[pr-commenter]

Benchmarks

Benchmark execution time: 2024-02-28 18:07:42

Comparing candidate commit c61de86 in PR branch bob/fix-crash-tracesender-fallback with baseline commit 552b0ef in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 182 metrics, 0 unstable metrics.

[PROFeNoM]

No tests 😝