Parallelize singleton execution.

Bug: 281536768
Test: manual, presubmits
Change-Id: I35fe5f4ce5732942399edf0d68e561039d7c253d
diff --git a/build/soong/sepolicy_freeze.go b/build/soong/sepolicy_freeze.go
index c5513d0..9ae7826 100644
--- a/build/soong/sepolicy_freeze.go
+++ b/build/soong/sepolicy_freeze.go
@@ -23,7 +23,7 @@
 
 func init() {
 	ctx := android.InitRegistrationContext
-	ctx.RegisterSingletonModuleType("se_freeze_test", freezeTestFactory)
+	ctx.RegisterParallelSingletonModuleType("se_freeze_test", freezeTestFactory)
 }
 
 // se_freeze_test compares the plat sepolicy with the prebuilt sepolicy.  Additional directories can