* Corrected the macro for comments on the test file.
* Added current_date (utcnow()) variable available for template macros.
* Removed unnecessary datetime import from macros file.
* Regenerated all practice exercise test files to add timestamp.
* Changed `datetime.now(tz=timezone.utc)` to `datetime.now(tz=timezone.utc).date()`
* Second regeneration to remove `timestamp` and just keep `date` for test files.
[no important files changed]
This test checks that different calls to `iter()` on the same
`LinkedList` instance return independent iterators, which
change state independently of each other.
