Update Skia expectations for quick_start_guide.pdf

Skia rendering only differs in minor ways, which are covered already by
other tests.

Bug: pdfium:1960
Change-Id: Ib8a9c467236d101069c877a4a34e521ada9157e4
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium_tests/+/103850
Reviewed-by: Nigi <nigi@chromium.org>