Support reordered pointer operands in local_bitvector_analysis

[tautschnig]

local_bitvector_analysist previously assumed that pointer arithmetic expressions with 3+ operands always have the pointer operand at position op0(). We do not, however, have such a requirement anywhere, and even if front-ends construct expressions this way then simplification may re-order the operands.

Fixes: #2689

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.93%. Comparing base (4fe3ade) to head (470747a).

Files with missing lines	Patch %	Lines
src/analyses/local_bitvector_analysis.cpp	0.00%	7 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #8785   +/-   ##
========================================
  Coverage    79.93%   79.93%           
========================================
  Files         1698     1698           
  Lines       187698   187703    +5     
  Branches        73       73           
========================================
+ Hits        150034   150047   +13     
+ Misses       37664    37656    -8     

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