Expand neverallow for sdk_version: none

Allow the platform stubs to specify sdk_version: none,
and add generic support for a regexp matcher.

Bug: 144149403
Test: m
Change-Id: Icaece0d9797bace8ae9741f7a029b9ea57fcbbb9

android/neverallow_test.go

@@ -226,6 +226,16 @@ var neverallowTests = []struct {
 				}`),
 		},
 	},
+	{
+		name: "sdk_version: \"none\" on android_*stubs_current stub",
+		fs: map[string][]byte{
+			"frameworks/base/Android.bp": []byte(`
+				java_library {
+					name: "android_stubs_current",
+					sdk_version: "none",
+				}`),
+		},
+	},
 	{
 		name: "sdk_version: \"none\" outside core libraries",
 		fs: map[string][]byte{