[ResourceScheduler] Make throttling H2+QUIC default disabled

testing/variations/fieldtrial_testing_config.json

 {
     "AndroidSessionNotifications": [
         {
             "platforms": [
                 "android"
             ],
             "experiments": [
                 {
                     "name": "Disabled"
                 }
@@ skipping 1368 matching lines @@
             "experiments": [
                 {
                     "name": "Enabled",
                     "enable_features": [
                         "PreferHtmlOverPlugins"
                     ]
                 }
             ]
         }
     ],
+    "PrioritySupportedRequestsDelayableStudy": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "mac",
+                "win",
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "PrioritySupportedRequestsDelayable"
+                    ]
+                }
+            ]
+        }
+    ],
     "ProgressBarAnimationAndroid": [
         {
             "platforms": [
                 "android"
             ],
             "experiments": [
                 {
                     "name": "SmoothIndeterminateAnimation",
                     "params": {
                         "progress-bar-animation": "smooth-indeterminate"
@@ skipping 836 matching lines @@
                 {
                     "name": "Enabled",
                     "enable_features": [
                         "use-new-media-cache"
                     ]
                 }
             ]
         }
     ]
 }