Add CriticlaPersistedTabData to fieldtrial_testing_config

This was determined to be necessary in cl/342061697

Bug: 1148823
Change-Id: I125e177fa057e6aebd92a0750559e4a68940c312
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537699Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: David Maunder <davidjm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827346}

testing/variations/fieldtrial_testing_config.json

@@ -1932,6 +1932,21 @@
             ]
         }
     ],
+    "CriticalPersistedTabData": [
+        {
+            "platforms": [
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "CriticalPersistedTabData"
+                    ]
+                }
+            ]
+        }
+    ],
     "CrosSchedulerCore": [
         {
             "platforms": [