Add field trial testing config for FormControlsRefresh

See launch bug: crbug.com/1042127

Bug: 1042127
Change-Id: Icd5d4977f0700ed40c1e3f2fbfaed39b5ee866fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2089708
Auto-Submit: Mason Freed <masonfreed@chromium.org>
Commit-Queue: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747880}

testing/variations/fieldtrial_testing_config.json

@@ -2227,6 +2227,24 @@
             ]
         }
     ],
+    "FormControlsRefresh": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "FormControlsRefresh"
+                    ]
+                }
+            ]
+        }
+    ],
     "ForwardMemoryPressureEventsToGpuProcess": [
         {
             "platforms": [