Deflake fast/text/decorations-transformed.html on Win7

Change fast/text/decorations-transformed.html to use the Ahem font
instead of ahem as test-only side-loaded fonts are case sensetive on
Windows. Also fix similar issue in line-break-after-question-mark
test.

BUG=378610
R=dglazkov@chromium.org

Review URL: https://codereview.chromium.org/316933003

git-svn-id: svn://svn.chromium.org/blink/trunk@175509 bbb929c8-8fbe-4397-9dbb-9b2b20218538