Add WebAssembly code gc field trial testing config

The feature was added in https://crrev.com/c/1578540. It's currently
finched in Canary and Dev and will soon be finched in beta (M-76).

R=jwd@chromium.org

Bug: 956480
Change-Id: I038e868fe5c43f3f8d214e62f6570ac1ef85d429
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1628615
Auto-Submit: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Jesse Doherty <jwd@chromium.org>
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663264}
diff --git a/testing/variations/fieldtrial_testing_config.json b/testing/variations/fieldtrial_testing_config.json
index ffe3c55..ab21c4f 100644
--- a/testing/variations/fieldtrial_testing_config.json
+++ b/testing/variations/fieldtrial_testing_config.json
@@ -5719,6 +5719,26 @@
             ]
         }
     ],
+    "V8WasmCodeGC": [
+        {
+            "platforms": [
+                "android",
+                "android_webview",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "WebAssemblyCodeGC"
+                    ]
+                }
+            ]
+        }
+    ],
     "VariationsHttpDisabled": [
         {
             "platforms": [