run() Windows error reporting

[tautschnig]

Adds reporting of system errors and a unit test thereof.

• 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 #5601 (80647dd) into develop (dcf92fe) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #5601   +/-   ##
========================================
  Coverage    69.33%   69.33%           
========================================
  Files         1242     1242           
  Lines       100412   100412           
========================================
  Hits         69616    69616           
  Misses       30796    30796           

Flag	Coverage Δ
cproversmt2	43.10% <ø> (ø)
regression	66.22% <ø> (ø)
unit	32.29% <ø> (+0.02%)	⬆️

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

Impacted Files	Coverage Δ
src/util/run.cpp	76.34% <ø> (ø)

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