can, isotp, soft: threding fixes and small buffer device support impr…

[BenGardiner]

Checklist :

• [Y] If you are new to Scapy: I have checked CONTRIBUTING.md (esp. section submitting-pull-requests)
• [Y] I squashed commits belonging together
• [Y] I added unit tests or explained why they are not relevant
• [Y] I executed the regression tests (using tox)
• [Y] If the PR is still not finished, please create a Draft Pull Request
• [Y] This PR uses (partially) AI-generated code. If so:
  • [Y] I ensured the generated code follows the internal concepts of scapy
  • [Y] This PR has a test coverage > 90%
  • [Y] I reviewed every generated line

I understand that failing to mention the use of AI may result in a ban. (We do not forbid it, but you must play fair. Be warned !)

• try harder to drain before close to avoid warnings
• unit tests to trigger issues encountered using soft sockt with slcan, candle, cantact on windows
• threading robustness improvements
• robustness improvements when using can adapters with small buffers
• improvements to the heuristics for detecting can adapters with no hardware filtering

cc @polybassa this is the isotp soft socket stuff extrated from PR #4961

[codecov]

Codecov Report

❌ Patch coverage is 72.28916% with 23 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.27%. Comparing base (1745d39) to head (603a69a).
⚠️ Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
scapy/contrib/cansocket_python_can.py	75.51%	12 Missing ⚠️
scapy/contrib/isotp/isotp_soft_socket.py	67.64%	11 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           master    #4983    +/-   ##
========================================
  Coverage   80.27%   80.27%            
========================================
  Files         382      383     +1     
  Lines       94349    94685   +336     
========================================
+ Hits        75736    76011   +275     
- Misses      18613    18674    +61     

Files with missing lines	Coverage Δ
scapy/contrib/isotp/isotp_soft_socket.py	84.50% <67.64%> (-0.03%)	⬇️
scapy/contrib/cansocket_python_can.py	84.37% <75.51%> (+0.84%)	⬆️

... and 9 files with indirect coverage changes

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[polybassa]

Looks good, beside this one comment.

Thanks for the PR.

[polybassa]

please remove the leftover unit test:

###(100)=[failed] UDS_Scanner reset_handler leaked socket causes CAN frame theft

[BenGardiner]

please remove the leftover unit test:

###(100)=[failed] UDS_Scanner reset_handler leaked socket causes CAN frame theft

sorry about that.

should be gone now