[blink scheduler] Enable intensive wake up throttling in testing config.

Bug: 1075553
Change-Id: I9ac77c32e96dba8a4f56fda637a8b7d0313b83aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2314456Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: François Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791236}

testing/variations/fieldtrial_testing_config.json

@@ -3668,6 +3668,24 @@
             ]
         }
     ],
+    "IntensiveWakeUpThrottling": [
+        {
+            "platforms": [
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "IntensiveWakeUpThrottling"
+                    ]
+                }
+            ]
+        }
+    ],
     "IntentBlockExternalFormRedirectsNoGesture": [
         {
             "platforms": [