Fix ignore flag for test attributes with values

[cry-inc]

See bug report #21435 for details on what case exactly is fixed.

Before this fix the ignore attribute would be only handled correctly when used like this:

#[test]
#[ignore]
fn example_a() {}

Now it can also handle cases where a an optional reason is specified:

#[test]
#[ignore = "some reason"]
fn example_b() {}

[ChayimFriedman2]

Thanks!