[io] Support reading long lines with _WindowsConsoleIO

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-09-24.00:33:09.827>
labels = ['OS-windows', 'expert-IO', 'type-feature', '3.10', 'expert-unicode', '3.9']
title = 'Support reading long lines with io._WindowsConsoleIO'
updated_at = <Date 2020-09-24.22:27:40.733>
user = 'https://github.com/eryksun'

bugs.python.org fields:

activity = <Date 2020-09-24.22:27:40.733>
actor = 'eryksun'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Unicode', 'Windows', 'IO']
creation = <Date 2020-09-24.00:33:09.827>
creator = 'eryksun'
dependencies = []
files = []
hgrepos = []
issue_num = 41849
keywords = []
message_count = 3.0
messages = ['377436', '377448', '377463']
nosy_count = 7.0
nosy_names = ['paul.moore', 'tim.golden', 'ezio.melotti', 'zach.ware', 'serhiy.storchaka', 'eryksun', 'steve.dower']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue41849'
versions = ['Python 3.9', 'Python 3.10']