Add hidden_api for java_import

Test: go java tests
Test: m
Bug: 160455085
Change-Id: Ib6e826e32ca73ceea0799b26145ad06b1e62a1bf
diff --git a/java/testing.go b/java/testing.go
index 1db6ef2..dc8f2a6 100644
--- a/java/testing.go
+++ b/java/testing.go
@@ -146,6 +146,7 @@
 				srcs: ["a.java"],
 				sdk_version: "none",
 				system_modules: "stable-core-platform-api-stubs-system-modules",
+				compile_dex: true,
 			}
 		`, extra)
 	}