Add arch property option

Change-Id: Id7fa934f8dbea0461b8dbe39c3575e72d5f9e02b
Bug: https://github.com/flutter/flutter/issues/135722
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/51420
Reviewed-by: Loïc Sharma <loicsharma@google.com>
Commit-Queue: Keyong Han <keyonghan@google.com>
diff --git a/recipe_modules/test_utils/__init__.py b/recipe_modules/test_utils/__init__.py
index fb75663..f2dc8ec 100644
--- a/recipe_modules/test_utils/__init__.py
+++ b/recipe_modules/test_utils/__init__.py
@@ -1,6 +1,7 @@
 DEPS = [
     'recipe_engine/context',
     'recipe_engine/platform',
+    'recipe_engine/properties',
     'recipe_engine/raw_io',
     'recipe_engine/step',
     'recipe_engine/swarming',
diff --git a/recipe_modules/test_utils/api.py b/recipe_modules/test_utils/api.py
index a6f3de4..9a9676f 100644
--- a/recipe_modules/test_utils/api.py
+++ b/recipe_modules/test_utils/api.py
@@ -262,6 +262,6 @@
     device_tags['device_version'] = 'none'
 
     device_tags['host_type'] = self.m.platform.name
-    device_tags['arch'] = self.m.platform.arch
+    device_tags['arch'] = self.m.properties.get('arch', self.m.platform.arch)
 
     return device_tags