fix conversions between long and long long

[kroening]

as_long in external_sat.cpp was declared as long long, computed as long, and subsequently passed to labs, which expects a long. This yields an error on any platform where long is not long long.

This changes the calculation to use long long consistently.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (52688d7) 79.09% compared to head (8db67b9) 79.09%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #8086   +/-   ##
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  Coverage    79.09%   79.09%           
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  Files         1701     1701           
  Lines       196625   196625           
========================================
  Hits        155527   155527           
  Misses       41098    41098           

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