Set LOCAL_PREBUILT_MODULE_FILE for hostdex modules

Java modules with hostdex: true have to manually create an extra
androidmk entry, which was missing LOCAL_PREBUILT_MODULE_FILE.

Test: m checkbuild
Change-Id: I9ecb853e149c83282738178f74c1c3a263d203cc
diff --git a/java/androidmk.go b/java/androidmk.go
index 7b81273..b9e4298 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -28,6 +28,11 @@
 		fmt.Fprintln(w, "LOCAL_MODULE := "+name+"-hostdex")
 		fmt.Fprintln(w, "LOCAL_IS_HOST_MODULE := true")
 		fmt.Fprintln(w, "LOCAL_MODULE_CLASS := JAVA_LIBRARIES")
+		if library.dexJarFile != nil {
+			fmt.Fprintln(w, "LOCAL_PREBUILT_MODULE_FILE :=", library.dexJarFile.String())
+		} else {
+			fmt.Fprintln(w, "LOCAL_PREBUILT_MODULE_FILE :=", library.implementationAndResourcesJar.String())
+		}
 		if library.installFile == nil {
 			fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE := true")
 		}