Fix goto-symex' auto-objects feature

[tautschnig]

The included test also demonstrates how to use it.

• Each commit message has a non-empty body, explaining why the change was made.
• n/a Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• n/a The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• n/a My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• n/a White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.39%. Comparing base (1ed7b2f) to head (e354f4e).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #7177      +/-   ##
===========================================
+ Coverage    78.38%   78.39%   +0.01%     
===========================================
  Files         1720     1720              
  Lines       187982   187990       +8     
  Branches     18474    18468       -6     
===========================================
+ Hits        147346   147372      +26     
+ Misses       40636    40618      -18     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[martin-cs]

Yes but we do have to be a little careful of the "don't give semantics to undefined behaviour" rule.