Restore conditional bounds-checking of count_{leading,trailing}_zeros

[tautschnig]

The cleanup of 4d4f9e7 (PR #6684) made bounds checking of these bit
count expressions unconditional. This did not affect any input coming
from the C front-end, but became apparent with the Rust front-end as
documented in model-checking/kani#886.

This commit restores conditional bounds checking, but now actually uses
the proper expression API rather than the low-level hack.

• 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

Merging #6708 (9ec216c) into develop (6594cbb) will decrease coverage by 0.35%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop    #6708      +/-   ##
===========================================
- Coverage    77.15%   76.79%   -0.36%     
===========================================
  Files         1582     1589       +7     
  Lines       182628   183488     +860     
===========================================
+ Hits        140900   140909       +9     
- Misses       41728    42579     +851     

Impacted Files	Coverage Δ
jbmc/src/janalyzer/janalyzer_parse_options.cpp	48.74% <ø> (ø)
jbmc/src/jbmc/jbmc_parse_options.cpp	75.97% <ø> (ø)
jbmc/src/jdiff/jdiff_parse_options.cpp	67.34% <ø> (ø)
src/goto-diff/goto_diff_parse_options.h	100.00% <ø> (ø)
.../goto-instrument/goto_instrument_parse_options.cpp	69.39% <ø> (ø)
...rc/goto-instrument/goto_instrument_parse_options.h	100.00% <ø> (ø)
src/goto-programs/goto_check.cpp	81.39% <ø> (ø)
src/goto-programs/process_goto_program.cpp	100.00% <ø> (ø)
src/ansi-c/goto_check_c.cpp	91.61% <100.00%> (ø)
src/goto-checker/properties.cpp	80.53% <100.00%> (+0.35%)	⬆️
... and 12 more

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