Given markdown:
  你好,中文
Execute (test clear errors):
    CheckChinese
    AssertEqual getqflist()[0].lnum, 1
    AssertEqual getqflist()[0].col, 7
    AssertEqual getqflist()[0].text[:3], 'E001'
    wincmd p
    call setline(1, '你好，中文')
    CheckChinese
    AssertEqual len(getqflist()), 0