[flang] Complete implementation of OUT_OF_RANGE() (#89334)
The intrinsic function OUT_OF_RANGE() lacks support in lowering and the
runtime. This patch obviates a need for any such support by implementing
OUT_OF_RANGE() via rewriting in semantics. This rewriting of
OUT_OF_RANGE() calls replaces the existing code that folds
OUT_OF_RANGE() calls with constant arguments.
Some changes and fixes were necessary outside of OUT_OF_RANGE()'s
folding code (now rewriting code), whose testing exposed some other
issues worth fixing.
- The common::RealDetails<> template class was recoded in terms of a new
base class with a constexpr constructor, so that the the characteristics
of the various REAL kinds could be queried dynamically as well. This
affected some client usage.
- There were bugs in the code that folds TRANSFER() when the type of X
or MOLD was REAL(10) -- this is a type that occupies 16 bytes per
element in execution memory but only 10 bytes (was 12) in the data of
std::vector<Scalar<>> in a Constant<>.
- Folds of REAL->REAL conversions weren't preserving infinities.
