Try again to fix the backdrop-animate-002 test on WPT.fyi

This test fails with off-by-one values on the green background. This
is attempt #2 to fix that, by adding fuzziness.

Bug: 1323293
Change-Id: I9f51f257ef0064b6cd144a32ae01b148ed881112
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3638193
Reviewed-by: Philip Rogers <pdr@chromium.org>
Auto-Submit: Mason Freed <masonf@chromium.org>
Commit-Queue: Mason Freed <masonf@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1001695}

Author: mfreed7

css/css-pseudo/backdrop-animate-002.html

@@ -5,6 +5,9 @@
 <link rel="help" href="https://fullscreen.spec.whatwg.org/#::backdrop-pseudo-element">
 <link rel="match" href="backdrop-animate-002-ref.html">
 <dialog id="target">Dialog contents</dialog>
+<!-- This test fails on WPT.fyi with off-by-one on the green background: -->
+<meta name=fuzzy content="maxDifference=1;totalPixels=472272">
+
 <style>
 #target::backdrop {
   will-change: transform;