Iterator/concat/next-method-returns-throwing-value-done.js is outdated

[woess]

test/built-ins/Iterator/concat/next-method-returns-throwing-value-done.js incorrectly throws ValueGetterError since tc39/proposal-iterator-sequencing#19 has introduced an extra IteratorValue step:

2. If _iteratorResult_ is ~done~, then
  a. Perform ? IteratorValue(_iteratorResult_).

The test should be changed to expect Iterator.concat getting the value of the iterator result when the underlying iterator is done.