Move old multicol tests to a separate directory.

LayoutTests/fast/multicol/float-paginate-empty-lines.html

-<p>This test is ensuring we don't grow the height of a block improperly when a float has no line association (e.g., when it's at the end of a
-block). The complete dashed border should be in the first column, with none of it appearing in the second column.</p>
-
-<div style="-moz-column-width:300px; -webkit-column-width:300px; column-width:300px; column-fill:auto; height:400px">
-<div style="border:10px dashed maroon">
-This is some text.<br>
-This is some text.<br>This is some text.<br>This is some text.<br>This is some text.<br>This is some text.<br>This is some text.<br>
-This is some text.<br>This is some text.<br>This is some text.<br>This is some text.<br>
-This is some text.<br>
-<img style="float:right;width:100px;height:200px;background-color:#cccccc">
-</div>