Add potential TLE testcases for two_sat

[PonderKoKo]

This adds one testcase (with symmetric variants) that leads to TLE on solutions that follow the structure:

1. Iterate over variables i (ascending / descending)
2. Try to set i = true (or false) and follow implications.
3. If this leads to a contradiction, revert changes, set i = false (or true) instead, and follow implications.

For example, I believe that the current fastest submission (https://judge.yosupo.jp/submission/230491) gets TLE on long_chain_01.

The structure of the testcase is quite simple, with a long implication chain to a contradiction, as described in the comment in the generator: // 1 -> 2, 2 -> 3, ..., n-1 -> n, n -> -n..

This is my first time contributing; let me know if I should make changes.

[maspypy]

There are no particular issues, so I merge it as is. Thank you.
I have also confirmed that the submission in question results in a TLE.
https://judge.yosupo.jp/hack/528