Mark test async_stream as executable_test

aschwaighofer · aschwaighofer · commit f82edf72c7a2 · 2021-05-13T06:26:10.000-07:00
It fails on non_executable bots.

rdar://77963528
diff --git a/test/Concurrency/Runtime/async_stream.swift b/test/Concurrency/Runtime/async_stream.swift
@@ -2,6 +2,7 @@
 
 // REQUIRES: concurrency
 // REQUIRES: libdispatch
+// REQUIRES: executable_test
 // UNSUPPORTED: use_os_stdlib
 
 // https://bugs.swift.org/browse/SR-14466
