Remove fast/multicol rebaseline request from TestExpectations

Rebaseline-o-matic failing to rebaseline these results: some issue with
changing to it's third_party/WebKit directory. Remove baseline requests
for multicol tests on Snowleopard Debug:

fast/multicol/pagination-h-horizontal-bt.html
fast/multicol/pagination-h-horizontal-tb.html
fast/multicol/pagination-v-horizontal-bt.html
fast/multicol/pagination-v-horizontal-tb.html
fast/multicol/client-rects.html

TBR=wangxianzhu@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=409708

Review URL: https://codereview.chromium.org/553673002

git-svn-id: svn://svn.chromium.org/blink/trunk@181525 bbb929c8-8fbe-4397-9dbb-9b2b20218538