use std::string_view for has_prefix, has_infix, has_suffix

[kroening]

The has_prefix function does not copy the given strings, and hence, using std::string_view can be used to relieve the caller from constructing the std::string object.

• 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/
• n/a 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).
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• My PR is restricted to a single feature or bugfix.
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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.83%. Comparing base (8575c6e) to head (e43324c).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #9099      +/-   ##
===========================================
- Coverage    80.84%   80.83%   -0.01%     
===========================================
  Files         1717     1717              
  Lines       190061   190075      +14     
  Branches        73       73              
===========================================
  Hits        153648   153648              
- Misses       36413    36427      +14     

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