[perl #126249] $/ constructed just once in [REGEX]

[Sam S. via RT]

This has been fixed by TimToday in April, in one of these commits:

    https://gist.github.com/Whateverable/23122ebe34ebeccfdfc3cd04845c54f4
    https://gist.github.com/smls/aff6a56c1cfcce5c7779251aee394e42

Tests needed.