[TaskGroup] temprorarily disable is async sequence test on linux

ktoso · ktoso · commit 163cb9efa0ac · 2021-02-26T17:54:03.000+09:00
diff --git a/test/Concurrency/Runtime/async_taskgroup_is_asyncsequence.swift b/test/Concurrency/Runtime/async_taskgroup_is_asyncsequence.swift
@@ -2,6 +2,7 @@
 
 // REQUIRES: executable_test
 // REQUIRES: concurrency
+// XFAIL: linux
 
 #if canImport(Darwin)
 import Darwin
