Add pixel tolerance for test animations/additive-transform-animations…

….html

https://bugs.webkit.org/show_bug.cgi?id=268086
rdar://121558830

Reviewed by Antoine Quint.

Add pixel tolerance.

* LayoutTests/animations/additive-transform-animations.html:

Canonical link: https://commits.webkit.org/273525@main

LayoutTests/animations/additive-transform-animations.html

@@ -1,3 +1,4 @@
+<meta name="fuzzy" content="maxDifference=0-1;totalPixels=0-1" />
 <style>
     #original {
         position: absolute;