[flang][runtime] (G0) for CHARACTER means (A), not (A0)

[klausler]

Summary

I'm emitting zero characters for (G0) formatting of CHARACTER values
instead of using their lengths to determine the output field width.

flang/runtime/edit-output.cpp

if (modes.delim) {
     list.set_lastWasUndelimitedCharacter(true);
   }
   return ok;
 }
 
 template <typename CHAR>
 bool EditCharacterOutput(IoStatementState &io, const DataEdit &edit,
     const CHAR *x, std::size_t length) {
+  int len{static_cast<int>(length)};
+  int width{edit.width.value_or(len)};
   switch (edit.descriptor) {
   case 'A':
+    break;
   case 'G':
+    if (width == 0) {
+      width = len;
+    }
     break;
   case 'B':
     return EditBOZOutput<1>(io, edit,
         reinterpret_cast<const unsigned char *>(x), sizeof(CHAR) * length);
   case 'O':
     return EditBOZOutput<3>(io, edit,
         reinterpret_cast<const unsigned char *>(x), sizeof(CHAR) * length);
   case 'Z':
     return EditBOZOutput<4>(io, edit,
         reinterpret_cast<const unsigned char *>(x), sizeof(CHAR) * length);
   default:
     io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
         "Data edit descriptor '%c' may not be used with a CHARACTER data item",
         edit.descriptor);
     return false;
   }
-  int len{static_cast<int>(length)};
-  int width{edit.width.value_or(len)};
   return io.EmitRepeated(' ', std::max(0, width - len)) &&
       io.EmitEncoded(x, std::min(width, len));
 }
 
 template bool EditIntegerOutput<1>(
     IoStatementState &, const DataEdit &, std::int8_t);
 template bool EditIntegerOutput<2>(
     IoStatementState &, const DataEdit &, std::int16_t);