[flang][runtime] Handle empty NAMELIST value list (llvm#151770)

InputNamelist() returns early if any value list read in by
InputDerivedType() or DescriptorIo<Input>() is empty, since they return
false. But an empty value list is okay, and the early return should
occur only on error.

Fixes llvm#151756.

Author: klausler

flang-rt/lib/runtime/namelist.cpp

@@ -578,12 +578,14 @@ bool IODEF(InputNamelist)(Cookie cookie, const NamelistGroup &group) {
         addendum && addendum->derivedType()) {
       const NonTbpDefinedIoTable *table{group.nonTbpDefinedIo};
       listInput->ResetForNextNamelistItem(/*inNamelistSequence=*/true);
-      if (!IONAME(InputDerivedType)(cookie, *useDescriptor, table)) {
+      if (!IONAME(InputDerivedType)(cookie, *useDescriptor, table) &&
+          handler.InError()) {
         return false;
       }
     } else {
       listInput->ResetForNextNamelistItem(useDescriptor->rank() > 0);
-      if (!descr::DescriptorIO<Direction::Input>(io, *useDescriptor)) {
+      if (!descr::DescriptorIO<Direction::Input>(io, *useDescriptor) &&
+          handler.InError()) {
         return false;
       }
     }