Clean up old field trials.

These have been launched and are now the default behavior on TOT.

Bug: 993325
Change-Id: Ide288a1c3c1333153799676ebc748d3bc1707a3b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2635661
Commit-Queue: Jakob Ivarsson <jakobi@google.com>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#844737}

testing/variations/fieldtrial_testing_config.json

@@ -7492,21 +7492,6 @@
             ]
         }
     ],
-    "WebRTC-Audio-NetEqDecisionLogicSettings": [
-        {
-            "platforms": [
-                "windows",
-                "mac",
-                "chromeos",
-                "linux"
-            ],
-            "experiments": [
-                {
-                    "name": "estimate_dtx_delay:true,time_stretch_cn:true"
-                }
-            ]
-        }
-    ],
     "WebRTC-Audio-NetEqDelayHistogram": [
         {
             "platforms": [
@@ -7541,25 +7526,6 @@
             ]
         }
     ],
-    "WebRTC-Audio-SendSideBwe": [
-        {
-            "platforms": [
-                "windows",
-                "mac",
-                "chromeos",
-                "linux",
-                "ios",
-                "android",
-                "android_weblayer",
-                "android_webview"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled"
-                }
-            ]
-        }
-    ],
     "WebRTC-CongestionWindow": [
         {
             "platforms": [
@@ -7579,24 +7545,6 @@
             ]
         }
     ],
-    "WebRTC-SendSideBwe-WithOverhead": [
-        {
-            "platforms": [
-                "windows",
-                "mac",
-                "chromeos",
-                "linux",
-                "ios",
-                "android",
-                "android_webview"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled"
-                }
-            ]
-        }
-    ],
     "WebRTC-TaskQueuePacer": [
         {
             "platforms": [