Value sets: track pointers through shifts

[tautschnig]

We already tracked pointers through other bit operations, but had not
taken shifts into account.

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[codecov]

Codecov Report

Merging #7024 (fef6c60) into develop (7ca319a) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop    #7024   +/-   ##
========================================
  Coverage    77.86%   77.86%           
========================================
  Files         1569     1569           
  Lines       180995   181004    +9     
========================================
+ Hits        140929   140938    +9     
  Misses       40066    40066           

Impacted Files	Coverage Δ
src/pointer-analysis/value_set.cpp	82.78% <100.00%> (+0.18%)	⬆️

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