Update CBMC version to 5.16.0

[NlightNFotis]

• 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.
• 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).
• My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[codecov]

Codecov Report

Merging #5520 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #5520   +/-   ##
========================================
  Coverage    68.40%   68.40%           
========================================
  Files         1187     1187           
  Lines        98090    98090           
========================================
  Hits         67102    67102           
  Misses       30988    30988           

Flag	Coverage Δ
#cproversmt2	42.97% <ø> (ø)
#regression	65.55% <ø> (ø)
#unit	32.25% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f10e6c7...fc2dfe6. Read the comment docs.