Add field trial testing config for Liftoff on mobile

We are currently finching on Canary and Dev, and want to promote to beta
soon. This field trial testing config contains the same three groups
used for finching.

R=bcwhite@chromium.org

Bug: 1040061, 1040030
Change-Id: Ibc43b37f74986166061290c4f92a9f5df8957d56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2022790Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735852}

testing/variations/fieldtrial_testing_config.json

@@ -7361,6 +7361,40 @@
             ]
         }
     ],
+    "V8WasmLiftoffMobile": [
+        {
+            "platforms": [
+                "android"
+            ],
+            "experiments": [
+                {
+                    "name": "Tiering",
+                    "enable_features": [
+                        "WebAssemblyBaseline",
+                        "WebAssemblyTiering"
+                    ]
+                },
+                {
+                    "name": "Liftoff",
+                    "enable_features": [
+                        "WebAssemblyBaseline"
+                    ],
+                    "disable_features": [
+                        "WebAssemblyTiering"
+                    ]
+                },
+                {
+                    "name": "TurboFan",
+                    "enable_features": [
+                        "WebAssemblyTiering"
+                    ],
+                    "disable_features": [
+                        "WebAssemblyBaseline"
+                    ]
+                }
+            ]
+        }
+    ],
     "VariationsHttpDisabled": [
         {
             "platforms": [