Removes WebRTC-VideoRateControl trial from test config

Bug: chromium:934391
Change-Id: I63c35a4954e3405217db5fd7820fb187242a8bfe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2518863
Auto-Submit: Erik Språng <sprang@chromium.org>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#824199}

testing/variations/fieldtrial_testing_config.json

@@ -7822,24 +7822,6 @@
             ]
         }
     ],
-    "WebRTC-VideoRateControl": [
-        {
-            "platforms": [
-                "windows",
-                "mac",
-                "chromeos",
-                "linux",
-                "ios",
-                "android",
-                "android_weblayer"
-            ],
-            "experiments": [
-                {
-                    "name": "pacing_factor:1.0,trust_vp8:true,trust_vp9:true,video_hysteresis:1.2,bitrate_adjuster:true,vp8_s0_boost:false"
-                }
-            ]
-        }
-    ],
     "WebRTC-Vp9ExternalRefCtrl": [
         {
             "platforms": [