Tell make that sh_test is a NATIVE_TEST

So that it ends up in VTS's DATA/nativetest like a cc_test, and
otherwise acts like a test.

Test: convert external/linux-kselftest to sh_test
Change-Id: I44b7cfca45f8fe5d7fbb6eaa845a79bd70f155ef

android/sh_binary.go

@@ -139,6 +139,7 @@ func (s *ShBinary) AndroidMk() AndroidMkData {
 
 func (s *ShTest) AndroidMk() AndroidMkData {
 	data := s.ShBinary.AndroidMk()
+	data.Class = "NATIVE_TESTS"
 	data.Extra = append(data.Extra, func(w io.Writer, outputFile Path) {
 		fmt.Fprintln(w, "LOCAL_COMPATIBILITY_SUITE :=",
 			strings.Join(s.testProperties.Test_suites, " "))