[analyzer] Improve handling of unsigned values in ArrayBoundCheckerV2 (#81034)

A memory access is an out of bounds error if the offset is < the extent
of the memory region. Notice that here "<" is a _mathematical_
comparison between two numbers and NOT a C/C++ operator that compares
two typed C++ values: for example -1 < 1000 is true in mathematics, but
if the `-1` is an `int` and the `1000` is a `size_t` value, then
evaluating the C/C++ operator `<` will return false because the `-1`
will be converted to `SIZE_MAX` by the automatic type conversions.

This means that it's incorrect to perform a bounds check with
`evalBinOpNN(State, BO_LT, ...)` which performs automatic conversions
and can produce wildly incorrect results.

ArrayBoundsCheckerV2 already had a special case where it avoided calling
`evalBinOpNN` in a situation where it would have performed an automatic
conversion; this commit replaces that code with a more general one that
covers more situations. (It's still not perfect, but it's better than
the previous version and I think it will cover practically all
real-world code.)

Note that this is not a limitation/bug of the simplification algorithm
defined in `getSimplifedOffsets()`: the simplification is not applied in
the test case `test_comparison_with_extent_symbol` (because the `Extent`
is not a concrete int), but without the new code it would still run into
a `-1 < UNSIGNED` comparison that evaluates to false because
`evalBinOpNN` performs an automatic type conversion.