Add config so perbots test tamper detection experiment

testing/variations/fieldtrial_testing_config_android.json

 {
     "AndroidSessionNotifications": [
         {
             "group_name": "Disabled"
         }
     ],
     "AsyncDns": [
         {
             "group_name": "AsyncDnsA"
         },
@@ skipping 82 matching lines @@
     "DataCompressionProxyPromoVisibility": [
         {
             "group_name": "Enabled"
         }
     ],
     "DataReductionProxyFREPromo": [
         {
             "group_name": "Enabled"
         }
     ],
+    "DataReductionProxyServerExperiments": [
+        {
+            "group_name": "TamperDetection_enabled"

[Alexei Svitkine (slow), 2016/06/09 21:48:14]

Actually, you should add a params section here to match your server config.

[bengr, 2016/06/10 23:21:14]

Done.

+        }
+    ],
     "DataReductionProxyUseQuic": [
         {
             "group_name": "Enabled"
         }
     ],
     "DisallowFetchForDocWrittenScriptsInMainFrame": [
         {
             "enable_features": [
                 "DocumentWriteEvaluator"
             ],
@@ skipping 419 matching lines @@
     ],
     "use-new-media-cache": [
         {
             "enable_features": [
                 "use-new-media-cache"
             ],
             "group_name": "Enabled"
         }
     ]
 }