Reset Mac baselines for un-antialiased text. (Unreviewed, massive baselines change).
(also zero-out the placeholder MacExpectations file).

TBR=
BUG=264088

git-svn-id: svn://svn.chromium.org/blink/trunk@155477 bbb929c8-8fbe-4397-9dbb-9b2b20218538