Add side_effect_expr_overflowt

[tautschnig]

Introduce a new expression to handle GCC's __builtin_X_overflow in the
middle-end (during goto conversion) instead of directly encoding the
semantics during type checking.

This commit is a refactoring only, it does not yet fix the bugs that #5544 intends to fix. #5544 will now be rebased on top of this commit.

• Each commit message has a non-empty body, explaining why the change was made.
• 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

Merging #5900 (1db0ad4) into develop (95e1161) will decrease coverage by 0.00%.
The diff coverage is 75.27%.

@@             Coverage Diff             @@
##           develop    #5900      +/-   ##
===========================================
- Coverage    75.02%   75.02%   -0.01%     
===========================================
  Files         1431     1433       +2     
  Lines       155595   155752     +157     
===========================================
+ Hits        116734   116850     +116     
- Misses       38861    38902      +41     

Impacted Files	Coverage Δ
src/ansi-c/c_typecheck_base.h	100.00% <ø> (ø)
src/goto-programs/goto_convert_class.h	87.30% <ø> (ø)
...rc/ansi-c/c_typecheck_gcc_polymorphic_builtins.cpp	76.58% <45.07%> (-4.36%)	⬇️
src/ansi-c/c_typecheck_expr.cpp	75.04% <81.81%> (-0.24%)	⬇️
src/ansi-c/c_expr.cpp	96.55% <96.55%> (ø)
src/goto-programs/goto_convert_side_effect.cpp	93.52% <96.66%> (+0.29%)	⬆️
src/ansi-c/c_expr.h	100.00% <100.00%> (ø)
...olvers/strings/string_constraint_instantiation.cpp	94.69% <0.00%> (+3.53%)	⬆️

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[kroening]

Same here now -- consider ansi-c/c_expr.h