[flang] preserve symbol in DescriptorInquiry

[jeanPerier]

Summary

Do not use ultimate symbols in DescriptorInquiry. Using the ultimate
symbol may lead to issues later for at least two reasons:

• The original symbols may have volatile/asynchronous attributes that the ultimate may not have. Later phases working on the DescriptorInquiry would then not apply potential care required by these attributes.
• HostAssociatedDetails symbols are used by OpenMP for symbols with special OpenMP attributes inside OpenMP region (e.g variables with private attribute), so it is very important to preserve this aspect in the DescriptorInquiry, that would otherwise apply on the symbol outside of the region.

[PeteSteinfeld]

All builds, tests, and looks good.

flang/lib/Evaluate/shape.cpp

return std::visit(
               return (*this)(subp.result());
             } else {
               return Result{};
             }
           },
           [&](const semantics::ProcBindingDetails &binding) {
             return (*this)(binding.symbol());
           },
-          [&](const semantics::UseDetails &use) {
-            return (*this)(use.symbol());
-          },
-          [&](const semantics::HostAssocDetails &assoc) {
-            return (*this)(assoc.symbol());
-          },
           [](const semantics::TypeParamDetails &) { return ScalarShape(); },
           [](const auto &) { return Result{}; },
       },
-      symbol.details());
+      symbol.GetUltimate().details());
 }
 
 auto GetShapeHelper::operator()(const Component &component) const -> Result {
   const Symbol &symbol{component.GetLastSymbol()};
   int rank{symbol.Rank()};
   if (rank == 0) {
     return (*this)(component.base());
   } else if (symbol.has<semantics::ObjectEntityDetails>()) {

flang/lib/Evaluate/variable.cpp

if (const auto *assoc{ultimate.detailsIf<semantics::AssocEntityDetails>()}) {
     if (const auto *chExpr{UnwrapExpr<Expr<SomeCharacter>>(assoc->expr())}) {
       return chExpr->LEN();
     }
   } else if (auto dyType{DynamicType::From(ultimate)}) {
     if (auto len{dyType->GetCharLength()}) {
       return len;
     } else if (IsDescriptor(ultimate) && !ultimate.owner().IsDerivedType()) {
       return Expr<SubscriptInteger>{DescriptorInquiry{
-          NamedEntity{ultimate}, DescriptorInquiry::Field::Len}};
+          NamedEntity{symbol}, DescriptorInquiry::Field::Len}};
     }
   }
   return std::nullopt;
 }
 
 std::optional<Expr<SubscriptInteger>> BaseObject::LEN() const {
   return std::visit(
       common::visitors{