Remove V8SiteIsolatedCodeCache from the testing config.

Bug: 1126640
Change-Id: Ie6027b53de6b832424d7c926581786aab5d4fe93
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2437023Reviewed-by: Mark Pearson <mpearson@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#812936}

testing/variations/fieldtrial_testing_config.json

@@ -7236,26 +7236,6 @@
             ]
         }
     ],
-    "V8SiteIsolatedCodeCache": [
-        {
-            "platforms": [
-                "android",
-                "android_weblayer",
-                "chromeos",
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "IsolatedCodeCache"
-                    ]
-                }
-            ]
-        }
-    ],
     "VideoCaptureService": [
         {
             "platforms": [