JNI lib is always embedded for APKs in APEX

If a JNI lib is depended on by an APK that is included in an APEX, the
lib is embedded inside the APK.

This change also fixes a bug that APKs are not mutated for APEXes.

Bug: 144135069
Test: m (apex_test.go amended)
Change-Id: Icf490d2701a7ede8bcad7e671fc72be9c8d7c01e

java/androidmk.go

@@ -262,6 +262,11 @@ func (binary *Binary) AndroidMkEntries() android.AndroidMkEntries {
 }
 
 func (app *AndroidApp) AndroidMkEntries() android.AndroidMkEntries {
+	if !app.IsForPlatform() {
+		return android.AndroidMkEntries{
+			Disabled: true,
+		}
+	}
 	return android.AndroidMkEntries{
 		Class:      "APPS",
 		OutputFile: android.OptionalPathForPath(app.outputFile),