[v8][wasm] Fix naming of finch trial tests in fieldtrial_testing_config.json

We have separate finch trials for the different platforms, so we should
use the same trial names here.

R=jwd@chromium.org

Bug: chromium:906565, chromium:903736
Change-Id: Icc6ca6d9074239ca277ccdf0546234b3626ed282
Reviewed-on: https://chromium-review.googlesource.com/c/1367664Reviewed-by: Jesse Doherty <jwd@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615850}

testing/variations/fieldtrial_testing_config.json

@@ -5119,9 +5119,7 @@
     "V8WasmTrapHandler": [
         {
             "platforms": [
-                "linux",
-                "windows",
-                "mac"
+                "linux"
             ],
             "experiments": [
                 {
@@ -5133,6 +5131,36 @@
             ]
         }
     ],
+    "V8WasmTrapHandlerMacOS": [
+        {
+            "platforms": [
+                "mac"
+            ],
+            "experiments": [
+                {
+                    "name": "WasmTrapHandlerMacOSActive",
+                    "enable_features": [
+                        "WebAssemblyTrapHandler"
+                    ]
+                }
+            ]
+        }
+    ],
+    "V8WasmTrapHandlerWindows": [
+        {
+            "platforms": [
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "WasmTrapHandlerWindowsActive",
+                    "enable_features": [
+                        "WebAssemblyTrapHandler"
+                    ]
+                }
+            ]
+        }
+    ],
     "VariationsHttpDisabled": [
         {
             "platforms": [