Rename animations pageset to tough_animation_cases

tools/perf/page_sets/tough_animation_cases.json

Index: tools/perf/page_sets/tough_animation_cases.json
diff --git a/tools/perf/page_sets/animations.json b/tools/perf/page_sets/tough_animation_cases.json
similarity index 81%
rename from tools/perf/page_sets/animations.json
rename to tools/perf/page_sets/tough_animation_cases.json
index d9e0e3e970406b7480a39c1502c4112c378286e9..10d839296a587d5dc5f347bf475839b3ec35d70c 100644
--- a/tools/perf/page_sets/animations.json
+++ b/tools/perf/page_sets/tough_animation_cases.json
@@ -2,7 +2,7 @@
   "description": "A collection of animation performance tests",
   "pages": [
     {
-      "url": "file:///animations/keyframed_animations.html",
+      "url": "file:///tough_animation_cases/keyframed_animations.html",
       "why": "Tests various keyframed animations.",
       "smoothness": {
         "action": "wait_interaction",
@@ -10,7 +10,7 @@
       }
     },
     {
-      "url": "file:///animations/transform_transitions.html",
+      "url": "file:///tough_animation_cases/transform_transitions.html",
       "why": "Tests various transitions.",
       "smoothness": {
         "action": "wait_interaction",