goto-harness: create goto binary or C output

[tautschnig]

It is not always necessary or desirable to produce C output. An ability
to produce goto binaries also avoids possible limitations of C and/or
dump-c (such as goto-harness creating initialisers for structs with bit
fields, which yield functions that take bit fields as parameters, which
isn't possible in C).

While at it, also clean up the help output to fix confusing language
about goto binaries when the output was actually C code.

• 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.
• 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

Merging #5821 (af01532) into develop (e76d811) will decrease coverage by 1.07%.
The diff coverage is 40.24%.

@@             Coverage Diff             @@
##           develop    #5821      +/-   ##
===========================================
- Coverage    75.12%   74.04%   -1.08%     
===========================================
  Files         1435     1444       +9     
  Lines       156301   157310    +1009     
===========================================
- Hits        117416   116485     -931     
- Misses       38885    40825    +1940     

Impacted Files	Coverage Δ
src/solvers/smt2/smt2_conv.h	100.00% <ø> (ø)
src/solvers/smt2/smt2_conv.cpp	59.95% <12.76%> (+0.56%)	⬆️
src/memory-analyzer/gdb_api.cpp	86.89% <50.00%> (ø)
src/goto-harness/goto_harness_parse_options.cpp	68.37% <60.00%> (-0.05%)	⬇️
unit/memory-analyzer/gdb_api.cpp	86.46% <94.73%> (ø)
src/goto-programs/link_goto_model.cpp	0.00% <0.00%> (-77.97%)	⬇️
src/ansi-c/literals/convert_character_literal.cpp	31.70% <0.00%> (-36.59%)	⬇️
...rc/ansi-c/c_typecheck_gcc_polymorphic_builtins.cpp	51.96% <0.00%> (-24.62%)	⬇️
src/goto-programs/remove_returns.cpp	74.84% <0.00%> (-24.53%)	⬇️
src/ansi-c/c_typecheck_base.cpp	55.37% <0.00%> (-22.87%)	⬇️
... and 55 more

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[martin-cs]

Looks to be an improvement.

Unhelpful suggestion : should it only ever generate goto binaries? If you want C then you can goto-instrument --dump-c output.gb. That would make the functionality more orthogonal. (But less user-friendly and would involve throwing away useful, working code, so, maybe not).

[tautschnig]

Unhelpful suggestion : should it only ever generate goto binaries? If you want C then you can goto-instrument --dump-c output.gb. That would make the functionality more orthogonal. (But less user-friendly and would involve throwing away useful, working code, so, maybe not).

Would probably be the better route forward, but we'd need to figure out a way of not breaking any customer's workflows. That seems hard to accomplish, I fear.

[chrisr-diffblue]

Looks good, and I'm happy for this to go in - with a personal-preference suggestion that you are totally free to ignore.