Add XP to needs rebaseline expectation for editing/spelling/inline-spelling-markers-hidpi-composited.html

Note: I don't think this is related to http://crbug.com/247716 but I couldn't add another NeedsManualRebaseline expectation for the same test.

NOTRY=true
TBR=jochen,enne
BUG=425143

Review URL: https://codereview.chromium.org/665133002

git-svn-id: svn://svn.chromium.org/blink/trunk@183993 bbb929c8-8fbe-4397-9dbb-9b2b20218538