C nondet symbol factory: arrays may have zero size

[tautschnig]

There is nothing fundamentally wrong in an array having size 0.

Fixes: #5093

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[codecov]

Codecov Report

Merging #6662 (f507eae) into develop (52d5788) will decrease coverage by 0.00%.
The diff coverage is 60.00%.

@@             Coverage Diff             @@
##           develop    #6662      +/-   ##
===========================================
- Coverage    76.81%   76.81%   -0.01%     
===========================================
  Files         1582     1582              
  Lines       182764   182776      +12     
===========================================
+ Hits        140399   140405       +6     
- Misses       42365    42371       +6     

Impacted Files	Coverage Δ
src/ansi-c/c_typecheck_expr.cpp	76.45% <50.00%> (-0.15%)	⬇️
src/ansi-c/c_nondet_symbol_factory.cpp	100.00% <100.00%> (ø)

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