[dartdev] skip a failing test on windows

Bug: https://github.com/dart-lang/sdk/issues/44679
Change-Id: Ibbb41f56ff8ee20567986a4497d14f43392acf90
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/179740
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Devon Carew <devoncarew@google.com>

pkg/dartdev/test/commands/language_server_test.dart

@@ -14,6 +14,9 @@ void main() {
     'language-server',
     defineLanguageServerTests,
     timeout: utils.longTimeout,
+    onPlatform: {
+      'windows': Skip('https://github.com/dart-lang/sdk/issues/44679'),
+    },
   );
 }