Remove expired RefreshTokenDeviceId experiment

BUG=799180
R=gayane@chromium.org

Change-Id: I83d0a362b9f52cfdf0db4e9eba48c6494dfcdad7
Reviewed-on: https://chromium-review.googlesource.com/1050978Reviewed-by: Gayane Petrosyan <gayane@chromium.org>
Commit-Queue: Pavel Yatsuk <pavely@chromium.org>
Cr-Commit-Position: refs/heads/master@{#557217}

testing/variations/fieldtrial_testing_config.json

@@ -2803,20 +2803,6 @@
             ]
         }
     ],
-    "RefreshTokenDeviceId": [
-        {
-            "platforms": [
-                "linux",
-                "mac",
-                "win"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled"
-                }
-            ]
-        }
-    ],
     "RemoveNavigationHistory": [
         {
             "platforms": [