Fix goto-instrument --dump-c parameter/local variable name collision

[tautschnig]

Local variables are automatically renamed with a unique suffix when a name collision is detected, producing valid compilable C code.

Co-authored-by: Kiro autonomous agent

Fixes: #6268

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.01%. Comparing base (7ff43f7) to head (3258237).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #8804   +/-   ##
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  Coverage    80.00%   80.01%           
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  Files         1700     1700           
  Lines       188271   188302   +31     
  Branches        73       73           
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+ Hits        150632   150661   +29     
- Misses       37639    37641    +2     

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[Copilot]

Pull request overview

Fixes goto-instrument --dump-c producing invalid C when a function parameter name collides with a local variable name, by renaming locals to a unique suffixed name.

Changes:

• Collect function parameter base-names before conversion to detect collisions.
• Rename local declarations on collision by updating the symbol’s base_name with a unique suffix.
• Add a regression test that exercises parameter/local collisions under --dump-c.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/goto-instrument/goto_program2code.h	Adds state for tracking parameter names and used local names; declares build_param_names().
src/goto-instrument/goto_program2code.cpp	Implements parameter name collection and local renaming on declaration when collisions are detected.
regression/goto-instrument/dump-param-local-collision/test.desc	Adds regression test driver for --dump-c collision case.
regression/goto-instrument/dump-param-local-collision/main.c	Test input containing parameter/local shadowing intended to trigger the dump-c renaming.

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