Fix: line longer than terminal width breaks rendering

[tompng]

This pull request fixes a bug introduced by #507
When you input long line, longer than the terminal width to irb and type enter, rendering breaks.

# Input data that I added in this pullrequest
def aaaaaaaaaa
  bbbbbbbbbb

# Before
prompt> def aaaaaaaa
prompt> def aaaaaaaa
aa
prompt>   bbbbbbbbbb
prompt>   bbbbbbbbbb
bb
prompt>

# After
prompt> def aaaaaaaa
aa
prompt>   bbbbbbbbbb
bb
prompt>

description

When newline is added to the end of the buffer, reline rerenders last line (because indent might changed) and the added newline.
When the last line is autowrapped (height of last line >= 2), cursor must move up before rerendering the last line, this pull request adds this process.

[st0012]

I wonder why test_multiline_and_autowrap didn't catch the issue. Is it because in that test inputs are added in a single writes?

[tompng]

test_multiline_and_autowrap writes at once, and I think writing at once is emulating pasting code.
Reline has in_pasting? check and I think it is making the difference

[ima1zumi]

👍