Remove IndexedDBHighPriority from the testing config.

Bug: 1126640
Change-Id: I9e0a1e799c205728784e6dbfb1cc9c2bf67c8575
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2626782Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#843599}

testing/variations/fieldtrial_testing_config.json

@@ -3638,32 +3638,6 @@
             ]
         }
     ],
-    "IndexedDBHighPriority": [
-        {
-            "platforms": [
-                "android",
-                "android_weblayer",
-                "chromeos",
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "HighPriorityDatabaseTaskType"
-                    ]
-                },
-                {
-                    "name": "Control",
-                    "disable_features": [
-                        "HighPriorityDatabaseTaskType"
-                    ]
-                }
-            ]
-        }
-    ],
     "InhibitBlobMemoryControllerMemoryPressureResponse": [
         {
             "platforms": [