bpo-38449: Add URL delimiters test cases (GH-16729) * bpo-38449: Add tricky test cases * bpo-38449: Reflect codereview (cherry picked from commit 2fe4c48917c2d1b40cf063c6ed22ae2e71f4cb62) Co-authored-by: Dong-hee Na <donghee.na92@gmail.com>