Upgrading to @testing-library/user-event 12.8.0 breaks the file upload test

[ahobson]

The test suite fails with 12.8.0. The failing test is:

 FAIL  src/components/forms/FileInput/FileInput.test.tsx
  ● FileInput component › uploading files › only shows previews for the most recently selected files if files are selected multiple times

    expect(element).not.toBeInTheDocument()

    expected document not to contain element, found <div aria-hidden="true" class="usa-file-input__preview" data-testid="file-input-preview"><img alt="" class="usa-file-input__preview-image is-loading" data-testid="file-input-preview-image" id="testimg_file__2exls" src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" />testFile.xls</div> instead

      175 |       // Change to no files
      176 |       userEvent.upload(inputEl, [])
    > 177 |       expect(queryByTestId('file-input-preview')).not.toBeInTheDocument()
          |                                                       ^
      178 |       expect(previewHeading).not.toBeInTheDocument()
      179 |       expect(getByTestId('file-input-instructions')).not.toHaveClass(
      180 |         'display-none'

      at Object.<anonymous> (src/components/forms/FileInput/FileInput.test.tsx:177:55)

There are changes changes to userEvent.upload in 12.8.0

[suzubara]

Closed by #1017