Bug 1832303 - Add Windows platform to custom-car tests in mach try perf. r=perftest-reviewers,sparky

We now have windows custom chromium-as-release available in-tree for windows 64 platform.
This patch makes those tasks available for selection via mach try perf.

Differential Revision: https://phabricator.services.mozilla.com/D177671

tools/tryselect/selectors/perfselector/classification.py

@@ -162,7 +162,7 @@ class ClassificationProvider:
                 "query": "'custom-car",
                 "negation": "!custom-car",
                 "restriction": check_for_custom_car,
-                "platforms": [Platforms.LINUX.value],
+                "platforms": [Platforms.LINUX.value, Platforms.WINDOWS.value],
             },
         }