Default metalava sandboxing to true

Turn on sandboxing everywhere.

Bug: 153703940
Test: m checkbuild
Change-Id: Ie64913d302efb780d5be9c1b32e6c368d72feba3
diff --git a/java/droidstubs_test.go b/java/droidstubs_test.go
index 6ad9323..f8125fb 100644
--- a/java/droidstubs_test.go
+++ b/java/droidstubs_test.go
@@ -34,6 +34,7 @@
 			srcs: ["bar-doc/a.java"],
 			api_levels_annotations_dirs: ["droiddoc-templates-sdk"],
 			api_levels_annotations_enabled: true,
+			sandbox: false,
 		}
 
 		droidstubs {
@@ -43,6 +44,7 @@
 			api_levels_annotations_dirs: ["droiddoc-templates-sdk"],
 			api_levels_annotations_enabled: true,
 			api_levels_jar_filename: "android.other.jar",
+			sandbox: false,
 		}
 		`,
 		map[string][]byte{