Fuzzing wpt tests to deal with scrollbar anti-alias.

Follow-up to CL:5362506

Adding fuzziness to more tests that are failing due to anti-aliasing
differences between composited and main-threaded Fluent scrollbars in
Windows. This CL adds fuzzy acceptance to the tests so that they'll
not fail due to this reason, which is not the main purpose of the
tests in question.

These tests were obtained by filtering the failing wpt tests in a
test CL that enables Fluent scrollbars by default and makes them paint
rounded thumbs (instead of square as they are now): CL:5593606

Bug: 326116366, 329199184
Change-Id: I701637ce3c1be0864009731548c2b7d0b1ef6ef1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5597461
Reviewed-by: Yaroslav Shalivskyy <yshalivskyy@microsoft.com>
Reviewed-by: Olga Gerchikov <gerchiko@microsoft.com>
Commit-Queue: Gaston Rodriguez <gastonr@microsoft.com>
Cr-Commit-Position: refs/heads/main@{#1310656}