FieldTrail - Added "delay_tcp_race": "true" as the default param when

testing/variations/fieldtrial_testing_config_mac.json

 {
     "AutofillClassifier": [
         {
             "group_name": "Enabled"
         }
     ],
     "AutofillFieldMetadata": [
         {
             "group_name": "Enabled"
         }
@@ skipping 28 matching lines @@
     "ChromeDashboard": [
         {
             "group_name": "Enabled"
         },
         {
             "group_name": "Default"
         }
     ],
     "ChromotingQUIC": [
         {
-            "group_name": "Enabled"
+            "group_name": "Enabled",
+            "params": {
+                "delay_tcp_race": "true"
+            }
         }
     ],
     "DocumentWriteEvaluator": [
         {
             "enable_features": [
                 "DocumentWriteEvaluator"
             ],
             "group_name": "Enabled"
         }
     ],
@@ skipping 278 matching lines @@
     ],
     "use-new-media-cache": [
         {
             "enable_features": [
                 "use-new-media-cache"
             ],
             "group_name": "Enabled"
         }
     ]
 }