Move animation svg tests to own subdirectory

third_party/WebKit/LayoutTests/animations/svg-composition-ignores-css-composition-flag.html

-<script src="../resources/testharness.js"></script>
-<script src="../resources/testharnessreport.js"></script>
-
-<div id="cssTarget"></div>
-<svg>
-  <rect id="svgTarget" color="red"></rect>
-</svg>
-
-<script>
-internals.disableCSSAdditiveAnimations();
-
-test(() => {
-  assert_throws('NotSupportedError', () => {
-    cssTarget.animate({color: 'red'});
-  });
-  assert_throws('NotSupportedError', () => {
-    cssTarget.animate([
-      {color: 'red'},
-      {color: 'red', composite: 'add'},
-    ]);
-  });
-}, 'Precheck that disabling CSS additive animations works.');
-
-test(() => {
-  var animation = svgTarget.animate({'svg-color': 'green'}, 1);
-  animation.pause();
-  animation.currentTime = 0.5;
-  assert_equals(getComputedStyle(svgTarget).color, 'rgb(128, 64, 0)');
-  animation.cancel();
-}, 'Neutral keyframes supported for SVG presentation attributes.');
-
-test(() => {
-  var keyframe = {'svg-color': 'green', composite: 'add'};
-  var animation = svgTarget.animate([keyframe, keyframe], {fill: 'forwards'});
-  assert_equals(getComputedStyle(svgTarget).color, 'rgb(255, 128, 0)');
-  animation.cancel();
-}, 'Additive keyframes supported for SVG presentation attributes.');
-</script>