Removing OptimizationHintsFetching Finch testing config.

This feature is now enabled by default
(https://chromium-review.googlesource.com/c/chromium/src/+/1887718) so
this is no longer needed in the json file.

Bug: 932707
Change-Id: Ibc5d43e788694857da94652e948e39d771a46b86
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894141Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Sophie Chang <sophiechang@chromium.org>
Commit-Queue: Michael Crouse <mcrouse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711689}

testing/variations/fieldtrial_testing_config.json

@@ -4096,25 +4096,6 @@
             ]
         }
     ],
-    "OptimizationHintsFetching": [
-        {
-            "platforms": [
-                "android"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled_20190804",
-                    "params": {
-                        "min_top_host_engagement_score_threshold": "2.0",
-                        "top_host_blacklist_size_multiplier": "3.0"
-                    },
-                    "enable_features": [
-                        "OptimizationHintsFetching"
-                    ]
-                }
-            ]
-        }
-    ],
     "OutOfBlinkCors": [
         {
             "platforms": [