`rustfix`: Fix ignored tests

[ehuss]

For some reason, several tests in rustfix are ignored:

• edition tests: https://github.com/rust-lang/cargo/blob/65d0eb536dd4a7ae6ddc50ca14556896e450c4ff/crates/rustfix/tests/parse_and_replace.rs#L242C1-L247. There don't appear to be any edition tests, so I think all of that should just be removed.
• These two proptests:

  cargo/crates/rustfix/src/replace.rs

  Lines 313 to 335 in 65d0eb5

  	proptest! {
  	#[test]
  	#[ignore]
  	fn new_to_vec_roundtrip(ref s in "\\PC*") {
  	assert_eq!(s.as_bytes(), Data::new(s.as_bytes()).to_vec().as_slice());
  	}
  	#[test]
  	#[ignore]
  	fn replace_random_chunks(
  	ref data in "\\PC*",
  	ref replacements in prop::collection::vec(
  	(any::<::std::ops::Range<usize>>(), any::<Vec<u8>>()),
  	1..1337,
  	)
  	) {
  	let mut d = Data::new(data.as_bytes());
  	for &(ref range, ref bytes) in replacements {
  	let _ = d.replace_range(range.clone(), bytes);
  	}
  	}
  	}
  	}

  . I'm guessing that these are ignored because they were either slow, or had errors. However, in my testing they seem to run pretty fast, so I'm guessing we could just remove the #[ignore]. This needs a little investigation, just to make sure these tests aren't flaky or anything.