Add expected files for print preview end to end testing on windows.

NOTRY=true

BUG=388517

Review URL: https://codereview.chromium.org/432133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287678 0039d316-1c4b-4281-b951-d872f2087c98

chrome/test/data/printing/layout_tests/TestExpectations

+# Test Expectations
+# These two tests have the same problem where the image that is being rendered is incomplete when printing to PDF.
+crbug.com/399756 [ Win Release ] source_html/colors/color-gradient.html [ ImageOnlyFailure ]
+crbug.com/399756 [ Win Release ] source_html/shapes/lines.html [ ImageOnlyFailure ]
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