Do not insert one extra emtpy line every 500 lines in the saved history.

The code for adding that extra empty line was introduced in commit
d3d909 (4 years ago). The reason and intention is not clear, so removing
those code might cause regression. Anyway, this commit is simple and can
be reverted easily, if unfortunately needed.

BUG: 225501
FIXED-IN: 4.8
REVIEW: 102652