[Mac 10.6] Rebaseline fast/text/justification-padding-mid-word.html

Test is reporting PASS on the Mac 10.6 try bot.

TBR=dstockwell@chromium.org
NOTRY=true
BUG=422050

Review URL: https://codereview.chromium.org/661643003

git-svn-id: svn://svn.chromium.org/blink/trunk@183777 bbb929c8-8fbe-4397-9dbb-9b2b20218538