Preopt APEX system server jars from prebuilts.

Similar to the previous CL, but for jars from prebuilts.

Test: manual - 1. Patch aosp/1818020 and aosp/1810840.
  2. m SOONG_CONFIG_art_module_source_build=false com.android.art
Bug: 194150908
Change-Id: Idc0c73a78045a602ad3a91cb5071d291bd611015
diff --git a/java/dexpreopt.go b/java/dexpreopt.go
index cdd42ed..b852615 100644
--- a/java/dexpreopt.go
+++ b/java/dexpreopt.go
@@ -160,6 +160,10 @@
 		}
 	}
 
+	if !android.IsModulePreferred(ctx.Module()) {
+		return true
+	}
+
 	// TODO: contains no java code
 
 	return false