Update xfermodes.pdf Skia expectation

Updates the Skia expectation for xfermodes.pdf after the fix for
crbug.com/pdfium/1959.

Bug: pdfium:1959
Change-Id: I765f470738bebc3c2b29a3199791630da6371a50
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium_tests/+/102490
Reviewed-by: Nigi <nigi@chromium.org>
1 file changed