Auto merge of #26407 - mrobinson:animation-restyle-model, r=jdm

Have animations more closely match the HTML spec

These two commits do two major things:

**Have animations ticks trigger a restyle**: This corrects synchronization issues with animations,
where the values used in layout are out of sync with what is returned by `getComputedStyle`.

**Tick the animation timer in script according to spec**: This greatly reduces the flakiness of
animation and transitions tests.

Fixes #13865.

<!-- Please describe your changes on the following line: -->

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #13865

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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tests/wpt/mozilla/meta/MANIFEST.json

@@ -12871,7 +12871,7 @@
       ]
      ],
      "transition-raf.html": [
-      "6159bb9ab333544b4485d11025889ee94186c7eb",
+      "c38404503408e04b3c75b42df18ec3a7ec0819f5",
       [
        null,
        {}

tests/wpt/mozilla/meta/css/animations/basic-transition.html.ini

@@ -1,3 +0,0 @@
-[basic-transition.html]
-  type: reftest
-  disabled: https://github.com/servo/servo/issues/13865

tests/wpt/mozilla/meta/css/animations/transition-raf.html.ini

@@ -1,3 +0,0 @@
-[transition-raf.html]
-  type: testharness
-  disabled: https://github.com/servo/servo/issues/13865

tests/wpt/mozilla/tests/css/animations/transition-raf.html

@@ -34,7 +34,7 @@ async_test(function(t) {
     assert_equals(getComputedStyle(box).getPropertyValue('width'), '100px');
     box.className = "expose";
     // Let the first restyle run at zero, then advance the clock.
-    setTimeout(function() { test.advanceClock(500, false) }, 0);
+    setTimeout(function() { test.advanceClock(500) }, 0);
   });
 }, "Transitions should work during RAF loop")
 </script>