Add kotlinx.coroutines to "neverallow" allowlist

Bug: 239834928
Test: manual -- all existing tests and builds should pass
Change-Id: Ie5fb0d6cbd8d624f71b80bb1afe003917410aa3d
diff --git a/android/neverallow.go b/android/neverallow.go
index aa47bca..e3bdd63 100644
--- a/android/neverallow.go
+++ b/android/neverallow.go
@@ -153,6 +153,7 @@
 	javaDeviceForHostProjectsAllowedList := []string{
 		"development/build",
 		"external/guava",
+		"external/kotlinx.coroutines",
 		"external/robolectric-shadows",
 		"frameworks/layoutlib",
 	}