[ci] Skip tests that aren't suppose to run on win (#1942)

.ci/scripts/dart_unit_tests_win32.sh

@@ -3,5 +3,5 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-dart pub global run flutter_plugin_tools test --packages-for-branch \
-  --log-timing
+dart pub global run flutter_plugin_tools test --exclude=script/configs/windows_unit_tests_exceptions.yaml \
+  --packages-for-branch --log-timing

.ci/targets/windows_dart_unit_tests.yaml

@@ -1,5 +1,5 @@
 tasks:
   - name: prepare tool
     script: .ci/scripts/prepare_tool.sh
-  - name: custom package tests
-    script: .ci/scripts/dart_unit_tests.sh
+  - name: dart unit tests
+    script: .ci/scripts/dart_unit_tests_win32.sh

script/configs/windows_unit_tests_exceptions.yaml

@@ -0,0 +1,8 @@
+# Packages that are excluded from dart unit test on Windows.
+
+# Exclude flutter_image because its tests need a test server, so are run via custom_package_tests.
+- flutter_image
+# TODO(chunhtai): Remove fuchsia_ctl if possible https://github.com/flutter/flutter/issues/103991.
+- fuchsia_ctl
+# TODO(chunhtai): Remove xgd_directories https://github.com/flutter/flutter/issues/103992.
+- xgd_directories