Support non-installable java libraries

Some java libraries will never be installed, support an
installable: false property and export it back to make as
LOCAL_UNINSTALLABLE_MODULE := true.

Test: m -j checkbuild, manually inspect out/soong/Android*.mk
Change-Id: I825ec897648c82fb7323da7df3539c9aaa6bcfce
diff --git a/java/androidmk.go b/java/androidmk.go
index 12643cf..c383a0e 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -29,6 +29,9 @@
 		Extra: []android.AndroidMkExtraFunc{
 			func(w io.Writer, outputFile android.Path) {
 				fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := .jar")
+				if library.properties.Installable != nil && *library.properties.Installable == false {
+					fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE := true")
+				}
 			},
 		},
 	}
@@ -41,6 +44,7 @@
 		Extra: []android.AndroidMkExtraFunc{
 			func(w io.Writer, outputFile android.Path) {
 				fmt.Fprintln(w, "LOCAL_MODULE_SUFFIX := .jar")
+				fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE := true")
 			},
 		},
 	}