Enable all struct tests under regression/cbmc/ for new SMT backend

[NlightNFotis]

Enable all struct tests under regression/cbmc/ for the new SMT backend (by marking them as new-smt-backend) and add two more regression tests for the case where the address-of operator is applied to a struct member.

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[NlightNFotis]

Despite the --z3 flag here, this does run with the new SMT backend when the test.pl profile for the new-smt-backend is run.

I have verified this locally, but I'm not sure I understand why that is - I speculate that the handling for the --incremental-smt2-solver flag is earlier, and path dependence handles the rest, but I haven't looked too close.

[thomasspriggs]

That matches my understanding. The --z3 flag is ignored when --incremental-smt2-solver is specified. Unfortunately the control flow for the solver_factory where this is handled is not always the easiest to follow.

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (f33b96a) 78.62% compared to head (eadb111) 78.63%.
Report is 6 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #7809   +/-   ##
========================================
  Coverage    78.62%   78.63%           
========================================
  Files         1701     1700    -1     
  Lines       195975   195974    -1     
========================================
+ Hits        154087   154095    +8     
+ Misses       41888    41879    -9     

see 15 files with indirect coverage changes

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[thomasspriggs]

⛏️ I am not sure this is a great test of the new SMT back end. The line field of expr will be at offset zero. It would be good to include taking the address of a field with a non-zero offset such as the comment field and to check that the resulting size of the offset is as expected.