Add native_bridge target to Android.bp

This allows us to build guest libraries for the native bridge for
arm/arm64 architectures.

Bug: http://b/77159578
Test: make
Change-Id: I35520ca456105ddadd456c78a4eb1e6de39147c5
diff --git a/java/dexpreopt.go b/java/dexpreopt.go
index a7938c8..08fd06e 100644
--- a/java/dexpreopt.go
+++ b/java/dexpreopt.go
@@ -111,7 +111,9 @@
 	if len(archs) == 0 {
 		// assume this is a java library, dexpreopt for all arches for now
 		for _, target := range ctx.Config().Targets[android.Android] {
-			archs = append(archs, target.Arch.ArchType)
+			if target.NativeBridge == android.NativeBridgeDisabled {
+				archs = append(archs, target.Arch.ArchType)
+			}
 		}
 		if inList(ctx.ModuleName(), global.SystemServerJars) && !d.isSDKLibrary {
 			// If the module is not an SDK library and it's a system server jar, only preopt the primary arch.