Move animation svg tests to own subdirectory

third_party/WebKit/LayoutTests/animations/clear-svg-animation-effects.html

-<script src="../resources/testharness.js"></script>
-<script src="../resources/testharnessreport.js"></script>
-<svg>
-  <stop id="target" offset="1"/>
-</svg>
-<script>
-var asyncHandle = async_test('SVG Attributes should return to their base values after animations have stopped applying.');
-
-var animation = target.animate([
-  {'svg-offset': '0'},
-  {'svg-offset': '0.5'},
-], 1000);
-animation.pause();
-animation.currentTime = 500;
-
-requestAnimationFrame(() => {
-  asyncHandle.step(() => {
-    assert_equals(target.offset.animVal, 0.25, 'Animation is in effect.');
-  });
-  animation.cancel();
-  requestAnimationFrame(() => {
-    asyncHandle.step(() => {
-      assert_equals(target.offset.animVal, 1, 'Animation is no longer in effect.');
-    });
-    asyncHandle.done();
-  });
-});
-</script>