Re-enable test fast/multicol/cell-shrinkback.html and make it pass.

Re-enable test fast/multicol/cell-shrinkback.html and make it pass.

Preferred min/max widths are rounded up for table cells, but not for other
types of shrink-to-fit containers, so using a table cell in the test and
an abspos in the ref doesn't necessarily result in identical rendering.

Specify a fixed width on the containers instead, so that the test isn't
affected by this problem. The problem has nothing to do with multicol.

BUG=397257
R=pkasting@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=180999

[Peter Kasting, 2014-08-27 19:45:04]

RS LGTM; if you want a real review by someone who understands the issues you'll
need to find someone else, I'm basically trusting you've done the right thing
since your explanation sounded plausible.

[mstensho (USE GERRIT), 2014-08-27 20:04:36]

The CQ bit was checked by mstensho@opera.com

[commit-bot: I haz the power, 2014-08-27 20:05:16]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mstensho@opera.com/501853003/1

[commit-bot: I haz the power, 2014-08-27 21:04:39]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_blink_compile_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/mac_blink_compile_dbg/bu...)
  linux_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/linux_gpu_trigger...)

[commit-bot: I haz the power, 2014-08-27 21:30:08]

Committed patchset #1 (id:1) as 180999