Port some css-multicol interpolation tests to WPT

Bug: 900581
Change-Id: Ia92d41788e13e7fb496b3e426d54622320f137cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1769306
Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690821}