Crangler: add loop invariants with loop numbers

[qinheping]

Crangler only supported to add a loop invariant to a specified for-loop or while-loop in a certain function. This PR adds support for adding loop invariants to loops specified by loop number, regardless they are for-loops or while-loops.

This PR is required when we annotate synthesized loop invariants back to c source code, because we don't know whether a loop in goto translated from a for-loop or a while-loop in the c code.

• 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 #7065 (b7f6948) into develop (d7b3f48) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #7065      +/-   ##
===========================================
+ Coverage    77.86%   77.92%   +0.05%     
===========================================
  Files         1569     1576       +7     
  Lines       180995   181615     +620     
===========================================
+ Hits        140929   141515     +586     
- Misses       40066    40100      +34     

Impacted Files	Coverage Δ
src/crangler/c_wrangler.cpp	75.51% <100.00%> (+15.75%)	⬆️
src/cpp/cpp_template_type.h	52.94% <0.00%> (-11.35%)	⬇️
src/goto-programs/goto_convert.cpp	88.12% <0.00%> (-4.22%)	⬇️
src/solvers/flattening/boolbv_quantifier.cpp	89.91% <0.00%> (-3.37%)	⬇️
...lvers/smt2_incremental/smt_response_validation.cpp	95.36% <0.00%> (-2.52%)	⬇️
src/util/type.h	98.59% <0.00%> (-1.41%)	⬇️
src/solvers/flattening/bv_utils.cpp	78.41% <0.00%> (-1.20%)	⬇️
src/solvers/smt2/smt2_format.cpp	85.39% <0.00%> (-1.13%)	⬇️
src/goto-instrument/contracts/cfg_info.h	84.21% <0.00%> (-0.79%)	⬇️
src/goto-programs/goto_convert_side_effect.cpp	94.47% <0.00%> (-0.74%)	⬇️
... and 67 more

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[jimgrundy]

@SaswatPadhi can you do a review first so we are making good use of our DiffBlue friends.