Add fieldtrial testing config for AppCacheCorruptionRecovery

This is so this can roll out to beta, however no tests should have
corrupted files and this is expected to be a noop.

Bug: 1033703
Change-Id: Iaca5ebfedd2fced012ccae8a5092bdb69071f2f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2450131
Auto-Submit: enne <enne@chromium.org>
Commit-Queue: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814195}

testing/variations/fieldtrial_testing_config.json

@@ -484,6 +484,28 @@
             ]
         }
     ],
+    "AppCacheCorruptionRecovery": [
+        {
+            "platforms": [
+                "android",
+                "android_weblayer",
+                "android_webview",
+                "chromeos",
+                "ios",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "AppCacheCorruptionRecovery",
+                    "enable_features": [
+                        "AppCacheCorruptionRecovery"
+                    ]
+                }
+            ]
+        }
+    ],
     "AppListLaunchRecorder": [
         {
             "platforms": [