Add "art/test" to the list of Core Library projects.

Allow modules under art/test to use `sdk_version: "none"`. This is so
that ART run-test module definitions can use the same settings as
Libcore tests:

  sdk_version: "none",
  system_modules: "core-all-system-modules",

Test: m nothing
Bug: 147814778
Change-Id: Ibb74d6a06a6609be511403c51ca7a02204bf606f
diff --git a/android/neverallow.go b/android/neverallow.go
index 26e42e6..526d399 100644
--- a/android/neverallow.go
+++ b/android/neverallow.go
@@ -145,11 +145,18 @@
 		"prebuilts",
 	}
 
-	// Core library constraints. The sdk_version: "none" can only be used in core library projects.
+	// Additional whitelisted path only used for ART testing, which needs access to core library
+	// targets. This does not affect the contents of a device image (system, vendor, etc.).
+	var artTests = []string{
+		"art/test",
+	}
+
+	// Core library constraints. The sdk_version: "none" can only be used in core library projects and ART tests.
 	// Access to core library targets is restricted using visibility rules.
 	rules := []Rule{
 		NeverAllow().
 			NotIn(coreLibraryProjects...).
+			NotIn(artTests...).
 			With("sdk_version", "none").
 			WithoutMatcher("name", Regexp("^android_.*stubs_current$")),
 	}